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LeetCode难题代码和算法要点分析

目前分类目录

Two Pointers

011.Container-With-Most-Water (M+)
015.3Sum (M)
016.3Sum-Closet (M)
018.4Sum (M)
259.3Sum-Smaller (M+)
030.Substring-with-Concatenation-of-All-Words (H)
075.Sort-Colors (M+)
026.Remove Duplicates from Sorted Array (H-)
080.Remove Duplicates from Sorted Array II (H)
209.Minimum-Size-Subarray-Sum (M)
088.Merge Sorted Array (M)
283.Move-Zeroes (M)
141.Linked-List-Cycle (E+)
142.Linked-List-Cycle-II (M+)
360.Sort-Transformed-Array (M)
713.Subarray-Product-Less-Than-K (M+)
923.3Sum-With-Multiplicity (H-)
1234.Replace-the-Substring-for-Balanced-String (H-)
1498.Number-of-Subsequences-That-Satisfy-the-Given-Sum-Condition (H-)
1574.Shortest-Subarray-to-be-Removed-to-Make-Array-Sorted (H-)
1580.Put-Boxes-Into-the-Warehouse-II (H-)
1687.Delivering-Boxes-from-Storage-to-Ports (H)
1793.Maximum-Score-of-a-Good-Subarray (M+)
1989.Maximum-Number-of-People-That-Can-Be-Caught-in-Tag (M+)
2354.Number-of-Excellent-Pairs (H-)
2422.Merge-Operations-to-Turn-Array-Into-a-Palindrome (H-)

• Sliding window
  532.K-diff-Pairs-in-an-Array (H-)
  611.Valid-Triangle-Number (M+)
  930.Binary-Subarrays-With-Sum (M+)
  1004.Max-Consecutive-Ones-III (M)
  1052.Grumpy-Bookstore-Owner (M)
  1358.Number-of-Substrings-Containing-All-Three-Characters (M)
  1838.Frequency-of-the-Most-Frequent-Element (H-)
  395.Longest-Substring-with-At-Least-K-Repeating-Characters (H)
  1763.Longest-Nice-Substring (H)
  2009.Minimum-Number-of-Operations-to-Make-Array-Continuous (M+)
  2024.Maximize-the-Confusion-of-an-Exam (M)
  424.Longest-Repeating-Character-Replacement (H-)
  2106.Maximum-Fruits-Harvested-After-at-Most-K-Steps (H)
  2401.Longest-Nice-Subarray (H-)
  2411.Smallest-Subarrays-With-Maximum-Bitwise-OR (H-)
  2516.Take-K-of-Each-Character-From-Left-and-Right (M+)
  2564.Substring-XOR-Queries (H-)
  2730.Find-the-Longest-Semi-Repetitive-Substring (M+)
  2747.Count-Zero-Request-Servers (H-)
• Sliding window : Distinct Characters
  076.Minimum-Window-Substring (M+)
  003.Longest-Substring-Without-Repeating-Character (E+)
  159.Longest-Substring-with-At-Most-Two-Distinct-Characters(H-)
  340.Longest-Substring-with-At-Most-K-Distinct-Characters (H)
  992.Subarrays-with-K-Different-Integers (H-)
  2461.Maximum-Sum-of-Distinct-Subarrays-With-Length-K (M)
  2537.Count-the-Number-of-Good-Subarrays (M+)
• Two pointers for two sequences
  986.Interval-List-Intersections (M)
  1229.Meeting-Scheduler (M+)
  1537.Get-the-Maximum-Score (H-)
  1577.Number-of-Ways-Where-Square-of-Number-Is-Equal-to-Product-of-Two-Numbers (H-)
  1775.Equal-Sum-Arrays-With-Minimum-Number-of-Operations (M+)
  1868.Product-of-Two-Run-Length-Encoded-Arrays (M+)
  2098.Subsequence-of-Size-K-With-the-Largest-Even-Sum (M+)

Binary Search

004.Median-of-Two-Sorted-Arrays (H)
153.Find-Minimum-in-Rotated-Sorted-Array (M+)
154.Find-Minimum-in-Rotated-Sorted-Array-II (H-)    
033.Search-in-Rotated-Sorted-Array (M)
081.Search-in-Rotated-Sorted-Array-II (M)
034.Search-for-a-Range (M)
162.Find-Peak-Element (H-)
222.Count-Complete-Tree-Nodes (H-)
275.H-index II (H)
302.Smallest-Rectangle-Enclosing-Black-Pixels (M+)
475.Heaters (H-)
483.Smallest-Good-Base (H)
029.Divide-Two-Integers (M+)
644.Maximum-Average-Subarray-II (H)
658.Find-K-Closest-Elements (H)
1095.Find-in-Mountain-Array (TBD)
1157.Online-Majority-Element-In-Subarray (H-)
1533.Find-the-Index-of-the-Large-Integer (M)
1712.Ways-to-Split-Array-Into-Three-Subarrays (H)
1889.Minimum-Space-Wasted-From-Packaging (H-)
1901.Find-a-Peak-Element-II (H)
2563.Count-the-Number-of-Fair-Pairs (M+)

• Binary Processing
  1483.Kth-Ancestor-of-a-Tree-Node (H)
  1922.Count-Good-Numbers (M)
• Binary Search by Value
  410.Split-Array-Largest-Sum (H-)
  774.Minimize-Max-Distance-to-Gas-Station (H)
  1011.Capacity-To-Ship-Packages-Within-D-Days (M)
  1060.Missing-Element-in-Sorted-Array (H)
  1102.Path-With-Maximum-Minimum-Value (H-)
  1631.Path-With-Minimum-Effort (H-)
  1231.Divide-Chocolate (M)
  1283.Find-the-Smallest-Divisor-Given-a-Threshold (M)
  1292.Maximum-Side-Length-of-a-Square-with-Sum-Less-than-or-Equal-to-Threshold (H-)
  1300.Sum-of-Mutated-Array-Closest-to-Target (M+)
  1482.Minimum-Number-of-Days-to-Make-m-Bouquets (M)
  1508.Range-Sum-of-Sorted-Subarray-Sums (M+)
  1552.Magnetic-Force-Between-Two-Balls (M)
  1608.Special-Array-With-X-Elements-Greater-Than-or-Equal-X (M+)
  1648.Sell-Diminishing-Valued-Colored-Balls (H-)
  1802.Maximum-Value-at-a-Given-Index-in-a-Bounded-Array (M+)
  1870.Minimum-Speed-to-Arrive-on-Time (M)
  1898.Maximum-Number-of-Removable-Characters (H-)
  1891.Cutting-Ribbons (E)
  2064.Minimized-Maximum-of-Products-Distributed-to-Any-Store (M)
  2071.Maximum-Number-of-Tasks-You-Can-Assign (H)
  2106.Maximum-Fruits-Harvested-After-at-Most-K-Steps (H)
  2137.Pour-Water-Between-Buckets-to-Make-Water-Levels-Equal (M)
  2141.Maximum-Running-Time-of-N-Computers (M+)
  2226.Maximum-Candies-Allocated-to-K-Children (M)
  2439.Minimize-Maximum-of-Array (H-)
  2517.Maximum-Tastiness-of-Candy-Basket (M+)
  2513.Minimize-the-Maximum-of-Two-Arrays (H)
  2528.Maximize-the-Minimum-Powered-City (H-)
  2557.Maximum-Number-of-Integers-to-Choose-From-a-Range-II (H-)
  2560.House-Robber-IV (H-)
  2594.Minimum-Time-to-Repair-Cars (M)
  2604.Minimum-Time-to-Eat-All-Grains (H-)
  2616.Minimize-the-Maximum-Difference-of-Pairs (H-)
  2702.Minimum-Operations-to-Make-Numbers-Non-positive (H-)
  • Find K-th Element
    215.Kth-Largest-Element-in-an-Array (M)
    287.Find-the-Duplicate-Number (H-)
    378.Kth-Smallest-Element-in-a-Sorted-Matrix (H-)
    373.Find-K-Pairs-with-Smallest-Sums (H)
    668.Kth-Smallest-Number-in-Multiplication-Table (H-)
    719.Find-Kth-Smallest-Pair-Distance (H-)
    1918.Kth-Smallest-Subarray-Sum (M+)
    2040.Kth-Smallest-Product-of-Two-Sorted-Arrays (H-)
    1439.Find-the-Kth-Smallest-Sum-of-a-Matrix-With-Sorted-Rows (H)
    786.Kth-Smallest-Prime-Fraction (H-)
    793.Preimage-Size-of-Factorial-Zeroes-Function (H-)
    1201.Ugly-Number-III (H-)
    1539.Kth-Missing-Positive-Number (H-)
    2387.Median-of-a-Row-Wise-Sorted-Matrix (H-)

Hash Map

049.Group-Anagrams (M+)
149.Max-Points-on-a-Line (H)
166.Fraction-to-Recurring-Decimal (M)
170.Two-Sum-III-Data-structure-design (M)
392.Is-Subsequence (H-)
274.H-Index (H)
325.Maximum-Size-Subarray-Sum-Equals-k (M)
409.Longest-Palindrome (M)
447.Number-of-Boomerangs (E+)
438.Find-All-Anagrams-in-a-String (M+)
356.Line-Reflection (H-)
594.Longest-Harmonious-Subsequence (M+)
532.K-diff-Pairs-in-an-Array (E+)
446.Arithmetic-Slices-II-Subsequence (H)
128.Longest-Consecutive-Sequence (H-)
753.Cracking-the-Safe (H)
890.Find-and-Replace-Pattern (M+)
939.Minimum-Area-Rectangle (M+)
982.Triples-with-Bitwise-AND-Equal-To-Zero (M+) (TBD)
1074.Number-of-Submatrices-That-Sum-to-Target (M+)
1487.Making-File-Names-Unique (M+)
1573.Number-of-Ways-to-Split-a-String (M)
2131.Longest-Palindrome-by-Concatenating-Two-Letter-Words (M)
2198.Number-of-Single-Divisor-Triplets (H-)

• Hash+Prefix
  525.Contiguous-Array (M)
  930.Binary-Subarrays-With-Sum (M)
  1983.Widest-Pair-of-Indices-With-Equal-Range-Sum (M)
  1442.Count-Triplets-That-Can-Form-Two-Arrays-of-Equal-XOR (H-)
  1524.Number-of-Sub-arrays-With-Odd-Sum (M)
  974.Subarray-Sums-Divisible-by-K (M)
  1590.Make-Sum-Divisible-by-P (M+)
  1658.Minimum-Operations-to-Reduce-X-to-Zero (M)
  1371.Find-the-Longest-Substring-Containing-Vowels-in-Even-Counts (H-)
  1542.Find-Longest-Awesome-Substring (H-)
  1915.Number-of-Wonderful-Substrings (M+)
  2025.Maximum-Number-of-Ways-to-Partition-an-Array (H)
  2488.Count-Subarrays-With-Median-K (H-)
  2489.Number-of-Substrings-With-Fixed-Ratio (H-)
  2588.Count-the-Number-of-Beautiful-Subarrays (M+)

Heap

220.Contains-Duplicate-III (M)
295.Find-Median-from-Data-Stream (M)
363.Max-Sum-of-Rectangle-No-Larger-Than-K (H)
352.Data-Stream-as-Disjoint-Intervals (H)
480.Sliding-Window-Median (H)
699.Falling-Squares (H)
729.My-Calendar-I (M)
855.Exam-Room (M+)
975.Odd-Even-Jump (H-)
632.Smallest-Range-Covering-Elements-from-K-Lists (H-)
1675.Minimize-Deviation-in-Array (H)
1296.Divide-Array-in-Sets-of-K-Consecutive-Numbers (M)
1348.Tweet-Counts-Per-Frequency (H-)
1488.Avoid-Flood-in-The-City (H-)
1606.Find-Servers-That-Handled-Most-Number-of-Requests (M)
1797.Design Authentication Manager (M)
1825.Finding-MK-Average (H)
1847.Closest-Room (M+)
1912.Design-Movie-Rental-System (M+)
2034.Stock Price Fluctuation (M)
2071.Maximum-Number-of-Tasks-You-Can-Assign (H)
2612.Minimum-Reverse-Operations (H)
2653.Sliding-Subarray-Beauty (M+)
2736.Maximum-Sum-Queries (H)

• Maintain intervals
  715.Range-Module (H)
  2213.Longest-Substring-of-One-Repeating-Character (H)
  2276.Count-Integers-in-Intervals (H-)
  2382.Maximum-Segment-Sum-After-Removals (M+)

Tree

144.Binary-Tree-Preorder-Traversal (M+)
145.Binary-Tree-Postorder-Traversal (H-)
270.Closest-Binary-Search-Tree-Value (M+)
095.Unique-Binary-Search-Trees-II (H)
094.Binary Tree Inorder Traversal (H-)
110.Balanced-Binary-Tree (M+)
222.Count-Complete-Tree-Nodes (M+)
099.Recover-Binary-Search-Tree (H)
114.Flatten-Binary-Tree-to-Linked-List (M+)
098.Validate-Binary-Search-Tree (M)
117.Populating Next Right Pointers in Each Node II (H)
156.Binary-Tree-Upside-Down (H)
285.Inorder-Successor-in-BST (M)
298.Binary-Tree-Longest-Consecutive Sequence (M+)
450.Delete-Node-in-a-BST (H)
437.Path-Sum-III (H-)
333.Largest-BST-Subtree (H)
572.Subtree-of-Another-Tree (M)
549.Binary-Tree-Longest-Consecutive-Sequence-II (M)
173.Binary-Search-Tree-Iterator (M)
545.Boundary-of-Binary-Tree (H-)
272.Closest-Binary-Search-Tree-Value-II (M+)
226.Invert-Binary-Tree (M)
655.Print-Binary-Tree (M+)
897.Increasing-Order-Search-Tree (M+)
501.Find-Mode-in-Binary-Search-Tree (M+)
558.Quad-Tree-Intersection (M+)
662.Maximum-Width-of-Binary-Tree (H-)
742.Closest-Leaf-in-a-Binary-Tree (H)
863.All-Nodes-Distance-K-in-Binary-Tree (H-)
958.Check-Completeness-of-a-Binary-Tree (M+)
1339. Maximum-Product-of-Splitted-Binary-Tree (TBD)
1104.Path-In-Zigzag-Labelled-Binary-Tree (M+)
1660.Correct-a-Binary-Tree (M+)
1666.Change-the-Root-of-a-Binary-Tree (H-)
1932.Merge-BSTs-to-Create-Single-BST (H)
2003.Smallest-Missing-Genetic-Value-in-Each-Subtree (H)
2277.Closest-Node-to-Path-in-Tree (H-)
2313.Minimum-Flips-in-Binary-Tree-to-Get-Result (H)
2322.Minimum-Score-After-Removals-on-a-Tree (H-)
2458.Height-of-Binary-Tree-After-Subtree-Removal-Queries (M+)
2467.Most-Profitable-Path-in-a-Tree (M+)
2445.Number-of-Nodes-With-Value-One (M+)

• Path in a tree
  543.Diameter-of-Binary-Tree (M)
  124.Binary-Tree-Maximum-Path-Sum (M)
  687.Longest-Univalue-Path (M+)
  1522.Diameter-of-N-Ary-Tree (M)
  2049.Count-Nodes-With-the-Highest-Score (M+)
  2246.Longest-Path-With-Different-Adjacent-Characters (M+)
  2538.Difference-Between-Maximum-and-Minimum-Price-Sum (H)
• Serialization & Hashing
  297.Serialize-and-Deserialize-Binary-Tree （H-）
  652.Find-Duplicate-Subtrees (H)
  1948.Delete-Duplicate-Folders-in-System (H)
• Tree & Sequence
  105.Construct-Binary-Tree-from-Preorder-and-Inorder-Traversal (H-)
  106.Construct-Binary-Tree-from-Inorder-and-Postorder-Traversal (M+)
  331.Verify-Preorder-Serialization-of-a-Binary-Tree (H)
  449.Serialize-and-Deserialize-BST (H)
  654.Maximum-Binary-Tree (H)
  971.Flip-Binary-Tree-To-Match-Preorder-Traversal (M+)
  1028.Recover-a-Tree-From-Preorder-Traversal (H-)
  1569.Number-of-Ways-to-Reorder-Array-to-Get-Same-BST (H)
  1597.Build-Binary-Expression-Tree-From-Infix-Expression (H)
  1902.Depth-of-BST-Given-Insertion-Order (H-)
• LCA
  1123.Lowest-Common-Ancestor-of-Deepest-Leaves (M+) (aka. LC.865)
  235.Lowest-Common-Ancestor-of-a-Binary-Search-Tree (M)
  236.Lowest-Common-Ancestor-of-a-Binary-Tree (M+)
  1644.Lowest-Common-Ancestor-of-a-Binary-Tree-II (M+)
  1676.Lowest-Common-Ancestor-of-a-Binary-Tree-IV (M+)
  1650.Lowest-Common-Ancestor-of-a-Binary-Tree-III (M)
  1740.Find-Distance-in-a-Binary-Tree (H)
  2096.Step-By-Step-Directions-From-a-Binary-Tree-Node-to-Another (M+)
  2509.Cycle-Length-Queries-in-a-Tree (M)
• N-ary Tree
  428.Serialize-and-Deserialize-N-ary-Tree (H)
  431.Encode-N-ary-Tree-to-Binary-Tree (H-)
  1516.Move-Sub-Tree-of-N-Ary-Tree (H-)
• Re-Root
  834.Sum-of-Distances-in-Tree (H)
  2581.Count-Number-of-Possible-Root-Nodes (H)
• 似树非树
  823, 1902,

Segment Tree

307.Range-Sum-Query-Mutable (H-)
1526.Minimum-Number-of-Increments-on-Subarrays-to-Form-a-Target-Array (H-)
1649.Create-Sorted-Array-through-Instructions (H-)
1157.Online-Majority-Element-In-Subarray (H)
370.Range-Addition (H)
218.The-Skyline-Problem (H+)
699.Falling-Squares (H)
715.Range-Module (H)
2286.Booking-Concert-Tickets-in-Groups (H-)
2407.Longest-Increasing-Subsequence-II (H-)
2569.Handling-Sum-Queries-After-Update (H)

[Binary Index Tree]

307.Range-Sum-Query-Mutable (M)
1649.Create-Sorted-Array-through-Instructions (H)
2031.Count-Subarrays-With-More-Ones-Than-Zeros (H)
2179.Count-Good-Triplets-in-an-Array (H)
2659.Make-Array-Empty (H)

Design

380.Insert-Delete-GetRandom-O(1) (M+)
381.Insert-Delete-GetRandom-O1-Duplicates-allowed (H-)
716.Max-Stack (M+)
355.Design-Twitter (H)
535.Encode-and-Decode-TinyURL (M)
631.Design-Excel-Sum-Formula (M+)
642.Design-Search-Autocomplete-System (M+)
895.Maximum-Frequency-Stack (H)
1146.Snapshot-Array (H)
1172.Dinner-Plate-Stacks (H)
1381.Design-a-Stack-With-Increment-Operation (H-)
1352.Product-of-the-Last-K-Numbers (M+)
1418.Display-Table-of-Food-Orders-in-a-Restaurant (H-)
1622.Fancy-Sequence (H+)
1801.Number-of-Orders-in-the-Backlog (M+)
2166.Design-Bitset (M+)

• Linked List
  146.LRU-Cache (H-)
  460.LFU Cache (H)
  432.All-O-one-Data-Structure (H)
  2289.Steps-to-Make-Array-Non-decreasing (H)
  2296.Design-a-Text-Editor (M+)

Stack

032.Longest-Valid-Parentheses (H)
155.Min-Stack (M)
225.Implement Stack using Queues (H-)
232.Implement-Queue-using-Stacks (H-)
341.Flatten-Nested-List-Iterator (M)
173.Binary-Search-Tree-Iterator (M)
536.Construct-Binary-Tree-from-String (M)
456.132-Pattern (H-)
636.Exclusive-Time-of-Functions (H-)
856.Score-of-Parentheses (M+)
946.Validate-Stack-Sequences（H-）
1190.Reverse-Substrings-Between-Each-Pair-of-Parentheses (H-)
1209.Remove-All-Adjacent-Duplicates-in-String-II (M+)
1586.Binary-Search-Tree-Iterator-II (H)
2197.Replace-Non-Coprime-Numbers-in-Array (H-)
2296.Design-a-Text-Editor (M+)
2751.Robot-Collisions (M+)
2764.is-Array-a-Preorder-of-Some-Binary-Tree (M+)

• monotonic stack: next greater / smaller
  042.Trapping-Rain-Water (H)
  084.Largest-Rectangle-in-Histogram (H)
  2334.Subarray-With-Elements-Greater-Than-Varying-Threshold (M+)
  085.Maximal-Rectangle (H-)
  255.Verify-Preorder-Sequence-in-Binary-Search-Tree (H)
  496.Next-Greater-Element-I (H-)
  503.Next-Greater-Element-II (H-)
  221.Maximal-Square (H-)
  654.Maximum-Binary-Tree (H)
  739.Daily-Temperatures (H-)
  768.Max-Chunks-To-Make-Sorted-II (H-)
  901.Online-Stock-Span (H-)
  907.Sum-of-Subarray-Minimums (H-)
  1856.Maximum-Subarray-Min-Product (M+)
  2104.Sum-of-Subarray-Ranges (H-)
  1019.Next-Greater-Node-In-Linked-List (M)
  1063.Number-of-Valid-Subarrays (M+)
  1124.Longest-Well-Performing-Interval (H)
  1950.Maximum-of-Minimum-Values-in-All-Subarrays (H-)
  1966.Binary-Searchable-Numbers-in-an-Unsorted-Array (M+)
  2434.Using-a-Robot-to-Print-the-Lexicographically-Smallest-String (H-)
  2454.Next-Greater-Element-IV (H-)
• monotonic stack: other usages
  962.Maximum-Width-Ramp (H)
  1130.Minimum-Cost-Tree-From-Leaf-Values (H)
  1944.Number-of-Visible-People-in-a-Queue (H)
  2282.Number-of-People-That-Can-Be-Seen-in-a-Grid (H)
  2289.Steps-to-Make-Array-Non-decreasing (H)
  2355.Maximum-Number-of-Books-You-Can-Take (H)
• form smallest sequence
  402.Remove-K-Digits (H-)
  1673.Find-the-Most-Competitive-Subsequence (M)
  2030.Smallest-K-Length-Subsequence-With-Occurrences-of-a-Letter (H)
  316.Remove-Duplicate-Letters (H)
  1081.Smallest-Subsequence-of-Distinct-Characters (M+)
  321.Create-Maximum-Number (H)
• parse expression
  071.Simplify-Path (M)
  224.Basic-Calculator(H-)
  227.Basic-Calculator-II (H-)
  772.Basic-Calculator-III (H)
  385.Mini-Parser (H)
  439.Ternary-Expression-Parser (H-)
  591.Tag-Validator (H)
  726.Number-of-Atoms (M+)
  1087.Brace-Expansion (H)
  1096.Brace-Expansion-II (H)
  1106.Parsing-A-Boolean-Expression (H-)
  1896.Minimum-Cost-to-Change-the-Final-Value-of-Expression (H+)

Deque

239.Sliding-Window-Maximum (H-)
862.Shortest-Subarray-with-Sum-at-Least-K (H)
1425.Constrained-Subsequence-Sum (H)
1438.Longest-Continuous-Subarray-With-Absolute-Diff-Less-Than-or-Equal-to-Limit (H)
1499.Max-Value-of-Equation (M+)
1562.Find-Latest-Group-of-Size-M (H)
1696.Jump-Game-VI (M+)
1776.Car-Fleet-II (H)
2398.Maximum-Number-of-Robots-Within-Budget (H-)
2762.Continuous-Subarrays (M+)

Priority Queue

004.Median-of-Two-Sorted-Arrays (H)
373.Find-K-Pairs-with-Smallest-Sums (H-)
871.Minimum-Number-of-Refueling-Stops (H-)
1057.Campus-Bikes (H-)
1167.Minimum-Cost-to-Connect-Sticks (H-)
1439.Find-the-Kth-Smallest-Sum-of-a-Matrix-With-Sorted-Rows (H-)
1642.Furthest-Building-You-Can-Reach (H-)
1705.Maximum-Number-of-Eaten-Apples (M+)
1792.Maximum-Average-Pass-Ratio (M+)
2263.Make-Array-Non-decreasing-or-Non-increasing (H)
2386.Find-the-K-Sum-of-an-Array (H+)

• 反悔贪心
  630.Course-Schedule-III (H)
  774.Minimize-Max-Distance-to-Gas-Station (H)
  2599.Make-the-Prefix-Sum-Non-negative (H-)
• Dual PQ
  1801.Number-of-Orders-in-the-Backlog (M)
  1882.Process-Tasks-Using-Servers (H)
  1942.The-Number-of-the-Smallest-Unoccupied-Chair (M+)
  2102.Sequentially-Ordinal-Rank-Tracker (H-)
  2402.Meeting-Rooms-III (M+)
  2653.Sliding-Subarray-Beauty (M+)
• Sort+PQ
  253.Meeting-Rooms-II (M+)
  502.IPO （M+）
  857.Minimum-Cost-to-Hire-K-Workers (H)
  1353.Maximum-Number-of-Events-That-Can-Be-Attended (H-)
  1383.Maximum-Performance-of-a-Team (M+)
  1834.Single-Threaded-CPU (M)
  1851.Minimum-Interval-to-Include-Each-Query (H)
  2406.Divide-Intervals-Into-Minimum-Number-of-Groups (M+)
  2542.Maximum-Subsequence-Score (M+)
• Arrangement with Stride
  767.Reorganize-String (M+)
  1054.Distant-Barcodes (M+)
  358.Rearrange-String-k-Distance-Apart (H-)
  621.Task-Scheduler (H-)
  984.String-Without-AAA-or-BBB (M+)
  1405.Longest-Happy-String (H-)
  1953.Maximum-Number-of-Weeks-for-Which-You-Can-Work (M+)
  2335.Minimum-Amount-of-Time-to-Fill-Cups (M+)

DFS

037.Sudoku-Solver (M+)
040.Combination-Sum-II (M+)
051.N-Queens (M)
131.Palindrome-Partitioning (M+)
291.Word-Pattern-II (M)
417.Pacific-Atlantic-Water-Flow (M)
200.Number-of-Islands (M)
282.Expression-Add-Operators (H)
312.Burst-Balloons (H-)
351.Android-Unlock-Patterns (H-)
399.Evaluate-Division (H-)
488.Zuma-Game (H-)
425.Word-Squares (H-)
959.Regions-Cut-By-Slashes (M+)
1306.Jump-Game-III (M)
1718.Construct-the-Lexicographically-Largest-Valid-Sequence (H-)
1766.Tree-of-Coprimes (H-)
2014.Longest-Subsequence-Repeated-k-Times (H)
2056.Number-of-Valid-Move-Combinations-On-Chessboard (H)
2065.Maximum-Path-Quality-of-a-Graph (M)

• search in an array
  090.Subsets-II (M+)
  301.Remove-Invalid-Parentheses (H)
  473.Matchsticks-to-Square (M+)
  491.Increasing-Subsequences (M)
  698.Partition-to-K-Equal-Sum-Subsets (H-)
  996.Number-of-Squareful-Arrays (H-)
  1307.Verbal-Arithmetic-Puzzle (H)
  1593.Split-a-String-Into-the-Max-Number-of-Unique-Substrings (M)
  1681.Minimum-Incompatibility (H)
  1723.Find-Minimum-Time-to-Finish-All-Jobs (H-)
  2305.Fair-Distribution-of-Cookies (H-)
  2597.The-Number-of-Beautiful-Subsets (M+)
• memorization
  329.Longest-Increasing-Path-in-a-Matrix (M)
  2328.Number-of-Increasing-Paths-in-a-Grid (M)
  638.Shopping-Offers (M+)
  403.Frog-Jump (M+)
  546.Remove-Boxes (H+)
  1340.Jump-Game-V (M+)
  1815.Maximum-Number-of-Groups-Getting-Fresh-Donuts (H-)
  2741.Special-Permutations (M+)
  2746.Decremental-String-Concatenation (H-)
• hidden matrix
  489.Robot-Room-Cleaner (H)
  1778.Shortest-Path-in-a-Hidden-Grid (H-)
  1810.Minimum-Path-Cost-in-a-Hidden-Grid (M+)

BFS

127.Word-Ladder (M+)
126.Word-Ladder-II (M+)
130.Surrounded-Regions (H-)
200.Number-of-Islands (H-)
490.The-Maze (M)
529.Minesweeper (M+)
637.Average-of-Levels-in-Binary-Tree (M)
675.Cut-Off-Trees-for-Golf-Event (M)
694.Number-of-Distinct-Islands (M+)
785.Is-Graph-Bipartite (M+)
815.Bus-Routes (M+)
838.Push-Dominoes (M+)
928.Minimize-Malware-Spread-II (H-)
1036.Escape-a-Large-Maze (H)
1245.Tree-Diameter (H)
1263.Minimum-Moves-to-Move-a-Box-to-Their-Target-Location (H)
1298.Maximum-Candies-You-Can-Get-from-Boxes (M+)
1311.Get-Watched-Videos-by-Your-Friends (M)
1345.Jump-Game-IV (M+)
1559.Detect-Cycles-in-2D-Grid (M)
1568.Minimum-Number-of-Days-to-Disconnect-Island (H-)
1617.Count-Subtrees-With-Max-Distance-Between-Cities (H-)
1654.Minimum-Jumps-to-Reach-Home (H-)
1905.Count-Sub-Islands (M+)
2045.Second-Minimum-Time-to-Reach-Destination (M+)
2101.Detonate-the-Maximum-Bombs (M+)
2258.Escape-the-Spreading-Fire (H+)
2290.Minimum-Obstacle-Removal-to-Reach-Corner (M+)
2493.Divide-Nodes-Into-the-Maximum-Number-of-Groups (H-)

• Multi State
  847.Shortest-Path-Visiting-All-Nodes (H-)
  864.Shortest-Path-to-Get-All-Keys (H-)
  913.Cat-and-Mouse (H+)
  1728.Cat-and-Mouse-II (H+)
  1293.Shortest-Path-in-a-Grid-with-Obstacles-Elimination (H-)
  1928.Minimum-Cost-to-Reach-Destination-in-Time (H-)
• 拓扑排序
  207.Course-Schedule (H-)
  210.Course-Schedule-II (M)
  269.Alien-Dictionary (H-)
  310.Minimum-Height-Trees (H-)
  444.Sequence-Reconstruction (H)
  802.Find-Eventual-Safe-States (H-)
  1136.Parallel-Courses (M)
  1203.Sort-Items-by-Groups-Respecting-Dependencies (H)
  1462.Course-Schedule-IV (M)
  1591.Strange-Printer-II (H-)
  1632.Rank-Transform-of-a-Matrix (H)
  1857.Largest-Color-Value-in-a-Directed-Graph (H-)
  2050.Parallel-Courses-III (M+)
  2115.Find-All-Possible-Recipes-from-Given-Supplies (M)
  2127.Maximum-Employees-to-Be-Invited-to-a-Meeting (H)
  2192.All-Ancestors-of-a-Node-in-a-Directed-Acyclic-Graph (M)
  2204.Distance-to-a-Cycle-in-Undirected-Graph (M)
  2392.Build-a-Matrix-With-Conditions (M+)
  2440.Create-Components-With-Same-Value (H-)
  2603.Collect-Coins-in-a-Tree (H-)
• Dijkstra (BFS+PQ)
  743.Network-Delay-Time (H-)
  407.Trapping-Rain-Water-II (H)
  778.Swim-in-Rising-Water (H)
  2503.Maximum-Number-of-Points-From-Grid-Queries (H-)
  505.The-Maze-II (H-)
  499.The-Maze-III (H)
  787.Cheapest-Flights-Within-K-Stops (H)
  882.Reachable-Nodes-In-Subdivided-Graph (H)
  1102.Path-With-Maximum-Minimum-Value (H-)
  1368.Minimum-Cost-to-Make-at-Least-One-Valid-Path-in-a-Grid (H)
  1514.Path-with-Maximum-Probability (H)
  1786.Number-of-Restricted-Paths-From-First-to-Last-Node (M+)
  1810.Minimum-Path-Cost-in-a-Hidden-Grid (M+)
  1976.Number-of-Ways-to-Arrive-at-Destination (M+)
  2093.Minimum-Cost-to-Reach-City-With-Discounts (H-)
  2714.Find-Shortest-Path-with-K-Hops (M+)
  2203.Minimum-Weighted-Subgraph-With-the-Required-Paths (H-)
  2473.Minimum-Cost-to-Buy-Apples (M)
  2577.Minimum-Time-to-Visit-a-Cell-In-a-Grid (H-)
  2662.Minimum-Cost-of-a-Path-With-Special-Roads (H-)
• Dijkstra (for Bipatite Graph)
  1066.Campus-Bikes-II (H+)
  1879.Minimum-XOR-Sum-of-Two-Arrays (H)
  1947.Maximum-Compatibility-Score-Sum (H)

Trie

208.Implement-Trie--Prefix-Tree (M+)
1804.Implement-Trie-II-(Prefix-Tree) (M+)
211.Add-and-Search-Word (H-)
472.Concatenated-Words (H-)
642.Design-Search-Autocomplete-System (H-)
648.Replace-Words (H)
588.Design-In-Memory-File-System (H-)
677.Map-Sum-Pairs (M)
676.Implement-Magic-Dictionary (H-)
139.Word-Break (M+)
140.Word-Break-II (M+)
212.Word-Search-II (H)
745.Prefix-and-Suffix-Search (H-)
1268.Search-Suggestions-System (H-)
1032. Stream of Characters (TBD)
1858.Longest-Word-With-All-Prefixes (M)
2416.Sum-of-Prefix-Scores-of-Strings (M)

• Trie and XOR
  421.Maximum-XOR-of-Two-Numbers-in-an-Array (H-)
  1707.Maximum-XOR-With-an-Element-From-Array (H-)
  1803.Count-Pairs-With-XOR-in-a-Range (H)
  1938.Maximum-Genetic-Difference-Query (H)
  2479.Maximum-XOR-of-Two-Non-Overlapping-Subtrees (H)

Linked List

061.Rotate-List (M)
082.Remove-Duplicates-from-Sorted-List-II (M+)
086.Partition-List (M)
142.Linked-List-Cycle-II (M+)
109.Convert-Sorted-List-to-Binary-Search-Tree (M)
369.Plus-One-Linked-List (M)
430.Flatten-a-Multilevel-Doubly-Linked-List (H-)
457.Circular-Array-Loop (H-)
708.Insert-into-a-Cyclic-Sorted-List (H-)
1474.Delete-N-Nodes-After-M-Nodes-of-a-Linked-List (M+)
1670.Design-Front-Middle-Back-Queue (M+)
1756.Design-Most-Recently-Used-Queue (H)

• Reverse Linked List
  206.Reverse-Linked-List (M)
  092.Reverse-Linked-List-II (M+)
  025.Reverse-Nodes-in-k-Group (M+)
  2074.Reverse-Nodes-in-Even-Length-Groups (H-)
  143.Reorder-List (H-)
  2046.Sort-Linked-List-Already-Sorted-Using-Absolute-Values (H-)

Dynamic Programming

264.Ugly-Number-II (H-)
313.Super-Ugly-Number (H-)
091.Decode-Ways (M)
639.Decode-Ways-II (H)
634.Find-the-Derangement-of-An-Array (H)
823.Binary-Trees-With-Factors (M+)
221.Maximal-Square (H-)
1277.Count-Square-Submatrices-with-All-Ones (M+)
600.Non-negative-Integers-without-Consecutive-Ones (H)
656.Coin-Path (H-)
818.Race-Car (H)
377.Combination-Sum-IV (M)
837.New-21-Game (H-)
887.Super-Egg-Drop (H)
1884.Egg-Drop-With-2-Eggs-and-N-Floors (H-)
920.Number-of-Music-Playlists (H)
940.Distinct-Subsequences-II (H)
1987.Number-of-Unique-Good-Subsequences (H)
446.Arithmetic-Slices-II-Subsequence (H-)
1027.Longest-Arithmetic-Sequence (M+)
1269.Number-of-Ways-to-Stay-in-the-Same-Place-After-Some-Steps (M+)
1316.Distinct-Echo-Substrings (M+)
1420.Build-Array-Where-You-Can-Find-The-Maximum-Exactly-K-Comparisons (H-)
1444. Number of Ways of Cutting a Pizza (TBD)
1531.String-Compression-II (H+)
1575.Count-All-Possible-Routes (M+)
1621.Number-of-Sets-of-K-Non-Overlapping-Line-Segments (H)
1639.Number-of-Ways-to-Form-a-Target-String-Given-a-Dictionary (H-)
1692.Count-Ways-to-Distribute-Candies (H-)
1787.Make-the-XOR-of-All-Segments-Equal-to-Zero (H)
1872.Stone-Game-VIII (H-)
1900.The-Earliest-and-Latest-Rounds-Where-Players-Compete (H)
1937.Maximum-Number-of-Points-with-Cost (H-)
1955.Count-Number-of-Special-Subsequences (H-)
2088.Count-Fertile-Pyramids-in-a-Land (H-)
2140.Solving-Questions-With-Brainpower (H)
2189.Number-of-Ways-to-Build-House-of-Cards (H-)
2218.Maximum-Value-of-K-Coins-From-Piles (H-)
2222.Number-of-Ways-to-Select-Buildings (M+)
2312.Selling-Pieces-of-Wood (M+)
2338.Count-the-Number-of-Ideal-Arrays (H)
2431.Maximize-Total-Tastiness-of-Purchased-Fruits (M+)
2484.Count-Palindromic-Subsequences (H-)
2713.Maximum-Strictly-Inreasing-Cells-in-a-Matrix (H-)

• 基本型 I
  198.House-Robber (E)
  213.House-Robber-II (M+)
  2597.The-Number-of-Beautiful-Subsets (H)
  2638.Count-the-Number-of-K-Free-Subsets (M+)
  2320.Count-Number-of-Ways-to-Place-Houses (M+)
  1388.Pizza-With-3n-Slices (H-)
  276.Paint-Fence (H-)
  265.Paint-House-II (H)
  1473.Paint-House-III (H-)
  376.Wiggle-Subsequence (H-)
  123.Best-Time-to-Buy-and-Sell-Stock-III (M+)
  188.Best-Time-to-Buy-and-Sell-Stock-IV (H)
  309.Best-Time-to-Buy-and-Sell-Stock-with-Cooldown (H-)
  714.Best-Time-to-Buy-and-Sell-Stock-with-Transaction-Fee (M+)
  514.Freedom-Trail (H-)
  740.Delete-and-Earn (H-)
  552.Student-Attendance-Record-II (H)
  801.Minimum-Swaps-To-Make-Sequences-Increasing (M)
  1223.Dice-Roll-Simulation (H-)
  1262.Greatest-Sum-Divisible-by-Three (M+)
  1363.Largest-Multiple-of-Three (H)
  1419.Minimum-Number-of-Frogs-Croaking (M)
  1548.The-Most-Similar-Path-in-a-Graph (M+)
  1746.Maximum-Subarray-Sum-After-One-Operation (M+)
  1824.Minimum-Sideway-Jumps (M)
  1839.Longest-Substring-Of-All-Vowels-in-Order (M)
  1883.Minimum-Skips-to-Arrive-at-Meeting-On-Time (H)
  2036.Maximum-Alternating-Subarray-Sum (M+)
  2143.Choose-Numbers-From-Two-Arrays-in-Range (H)
  2318.Number-of-Distinct-Roll-Sequences (H-)
  2361.Minimum-Costs-Using-the-Train-Line (M+)
• 基本型 II
  368.Largest-Divisible-Subset (M+)
  300.Longest-Increasing-Subsequence (M+)
  673.Number-of-Longest-Increasing-Subsequence (M+)
  960.Delete-Columns-to-Make-Sorted-III (H-)
  983.Minimum-Cost-For-Tickets (H-)
  1043.Partition-Array-for-Maximum-Sum(M+)
  1105.Filling-Bookcase-Shelves (H-)
  1959.minimum-total-space-wasted-with-k-resizing-operations (H-)
  2052.Minimum-Cost-to-Separate-Sentence-Into-Rows (H-)
  1416.Restore-The-Array (M+)
  1546.Maximum-Number-of-Non-Overlapping-Subarrays-With-Sum-Equals-Target (M+)
  1626.Best-Team-With-No-Conflicts (M)
  1691.Maximum-Height-by-Stacking-Cuboids (H)
  2188.Minimum-Time-to-Finish-the-Race (H-)
  2209.Minimum-White-Tiles-After-Covering-With-Carpets (M+)
  2430.Maximum-Deletions-on-a-String (M+)
  2464.Minimum-Subarrays-in-a-Valid-Split (M)
  2522.Partition-String-Into-Substrings-With-Values-at-Most-K (M+)
• 走迷宫型
  120.Triangle (E)
  174.Dungeon-Game (H-)
  741.Cherry-Pickup (H-)
  1463.Cherry-Pickup-II (M)
  576.Out-of-Boundary-Paths (H)
  931.Minimum-Falling-Path-Sum (M)
  1289.Minimum-Falling-Path-Sum-II (M+)
  1301.Number-of-Paths-with-Max-Score (M+)
  1594.Maximum-Non-Negative-Product-in-a-Matrix (M)
  2267.Check-if-There-Is-a-Valid-Parentheses-String-Path (H-)
  2435.Paths-in-Matrix-Whose-Sum-Is-Divisible-by-K (M)
• 背包型
  322.Coin-Change (M)
  416.Partition-Equal-Subset-Sum (M+)
  518.Coin-Change-2 (H-)
  474.Ones-and-Zeroes (H-)
  494.Target-Sum (M+)
  805.Split-Array-With-Same-Average (H)
  879.Profitable-Schemes (M+)
  956.Tallest-Billboard (H)
  1049.Last-Stone-Weight-II (H-)
  1449.Form-Largest-Integer-With-Digits-That-Add-up-to-Target (H-)
  1981.Minimize-the-Difference-Between-Target-and-Chosen-Elements (M+)
  2291.Maximum-Profit-From-Trading-Stocks (M)
  2518.Number-of-Great-Partitions (H-)
  2585.Number-of-Ways-to-Earn-Points (M)
• 键盘型
  650.2-Keys-Keyboard (M+)
  651.4-Keys-Keyboard (M+)
  935.Knight-Dialer (M)
  1320.Minimum-Distance-to-Type-a-Word-Using-Two-Fingers (H)
• To Do or Not To Do
  487.Max-Consecutive-Ones-II (H-)
  1186.Maximum-Subarray-Sum-with-One-Deletion (H-)
  1187.Make-Array-Strictly-Increasing (H-)
  1909.Remove-One-Element-to-Make-the-Array-Strictly-Increasing (H-)
• 区间型 I
  132.Palindrome-Partitioning-II (H-)
  410.Split-Array-Largest-Sum (H)
  813.Largest-Sum-of-Averages (H-)
  1278.Palindrome-Partitioning-III (H)
  1335.Minimum-Difficulty-of-a-Job-Schedule (M+)
  1478.Allocate-Mailboxes (H)
  1977.Number-of-Ways-to-Separate-Numbers (H)
  2463.Minimum-Total-Distance-Traveled (M+)
  2472.Maximum-Number-of-Non-overlapping-Palindrome-Substrings (M+)
  2478.Number-of-Beautiful-Partitions (H-)
  2547.Minimum-Cost-to-Split-an-Array (M)
• 区间型 II
  131.Palindrome-Partitioning (M+)
  312.Burst-Balloons (H-)
  375.Guess-Number-Higher-or-Lower-II (H)
  471.Encode-String-with-Shortest-Length (H)
  516.Longest-Palindromic-Subsequence (H-)
  546.Remove-Boxes (H+)
  664.Strange-Printer (H)
  730.Count-Different-Palindromic-Subsequences (H)
  1000.Minimum-Cost-to-Merge-Stones (H)
  1130.Minimum-Cost-Tree-From-Leaf-Values (M+)
  1246.Palindrome-Removal (H)
  1039.Minimum-Score-Triangulation-of-Polygon (H)
  1547.Minimum-Cost-to-Cut-a-Stick (M)
  1682.Longest-Palindromic-Subsequence-II (H)
  1690.Stone-Game-VII (H-)
  1745.Palindrome-Partitioning-IV (M)
  1770.Maximum-Score-from-Performing-Multiplication-Operations (H-)
• 双序列型
  010.Regular-Expression-Matching (H)
  044.Wildcard-Matching (H-)
  097.Interleaving-String (H-)
  072.Edit-Distance (H-)
  115.Distinct-Subsequences (H-)
  583.Delete-Operation-for-Two-Strings (M+)
  712.Minimum-ASCII-Delete-Sum-for-Two-Strings (M+)
  718.Maximum-Length-of-Repeated-Subarray (M)
  727.Minimum-Window-Subsequence (H-)
  1035.Uncrossed-Lines (M)
  1092.Shortest-Common-Supersequence (H-)
  1143.Longest-Common-Subsequence (M)
  1216.Valid-Palindrome-III (M+)
  1312.Minimum-Insertion-Steps-to-Make-a-String-Palindrome (M+)
  1458.Max-Dot-Product-of-Two-Subsequences (M)
  1771.Maximize-Palindrome-Length-From-Subsequences (H)
• 状态压缩DP
  465.Optimal-Account-Balancing (H)
  691.Stickers-to-Spell-Word (H)
  1125.Smallest-Sufficient-Team (H)
  1349.Maximum-Students-Taking-Exam (H)
  1411.Number-of-Ways-to-Paint-N×3-Grid (M)
  1434.Number-of-Ways-to-Wear-Different-Hats-to-Each-Other (H-)
  1659.Maximize-Grid-Happiness (H)
  1681.Minimum-Incompatibility (H)
  1723.Find-Minimum-Time-to-Finish-All-Jobs (H-)
  1799.Maximize-Score-After-N-Operations (H-)
  1931.Painting-a-Grid-With-Three-Different-Colors (M+)
  1994.The-Number-of-Good-Subsets (H)
  2184.Number-of-Ways-to-Build-Sturdy-Brick-Wall (H-)
  2403.Minimum-Time-to-Kill-All-Monsters (M+)
  2572.Count-the-Number-of-Square-Free-Subsets (H-)
  • 枚举集合的子集
    1494.Parallel-Courses-II (H)
    1655.Distribute-Repeating-Integers (H)
    1986.Minimum-Number-of-Work-Sessions-to-Finish-the-Tasks (M+)
    2152.Minimum-Number-of-Lines-to-Cover-Points (H-)
  • 带权二分图
    1066.Campus-Bikes-II (H+)
    1595.Minimum-Cost-to-Connect-Two-Groups-of-Points (H)
    1879.Minimum-XOR-Sum-of-Two-Arrays (H)
    1947.Maximum-Compatibility-Score-Sum (H)
    2172.Maximum-AND-Sum-of-Array (H)
  • TSP
    943.Find-the-Shortest-Superstring (H+)
    2247.Maximum-Cost-of-Trip-With-K-Highways (H)
• Catalan
  096.Unique-Binary-Search-Trees (M+)
  1259.Handshakes-That-Don't-Cross (M+)
• Permutation
  629.K-Inverse-Pairs-Array (H)
  903.Valid-Permutations-for-DI-Sequence (H)
  1866.Number-of-Ways-to-Rearrange-Sticks-With-K-Sticks-Visible (H)
• Infer future from current
  2044.Count-Number-of-Maximum-Bitwise-OR-Subsets (M)
  2742.Painting-the-Walls (H)
• maximum subarray
  053.Maximum-Subarray (E+)
  152.Maximum-Product-Subarray (M+)
  2272.Substring-With-Largest-Variance (H-)
  2321.Maximum-Score-Of-Spliced-Array (H-)

Bit Manipulation

137.Single-Number-II (H-)
260.Single-Number-III (H)
371.Sum-of-Two-Integers (H)
318.Maximum-Product-of-Word-Lengths (M+)
342.Power-of-Four (H)
898.Bitwise-ORs-of-Subarrays (H-)
957.Prison-Cells-After-N-Days (H)
1461.Check-If-a-String-Contains-All-Binary-Codes-of-Size-K (TBD)
1521.Find-a-Value-of-a-Mysterious-Function-Closest-to-Target (H-)
2505.Bitwise-OR-of-All-Subsequence-Sums (H)
2680.Maximum-OR (M+)

• XOR
  136.Single-Number (M)
  268.Missing-Number (H-)
  1310.XOR-Queries-of-a-Subarray (M)
  1442.Count-Triplets-That-Can-Form-Two-Arrays-of-Equal-XOR (M+)
  1506.Find-Root-of-N-Ary-Tree (M+)
  1734.Decode-XORed-Permutation (M+)
  1738.Find-Kth-Largest-XOR-Coordinate-Value (M+)
  1835.Find-XOR-Sum-of-All-Pairs-Bitwise-AND (M)
  2527.Find-Xor-Beauty-of-Array (H)
• Bit Mask
  320.Generalized-Abbreviation (M)
  1239.Maximum-Length-of-a-Concatenated-String-with-Unique-Characters (M+)
  1284.Minimum-Number-of-Flips-to-Convert-Binary-Matrix-to-Zero-Matrix (M+)
  1452.People-Whose-List-of-Favorite-Companies-Is-Not-a-Subset-of-Another-List (H-)
  1601.Maximum-Number-of-Achievable-Transfer-Requests (H-)
  1774.Closest-Dessert-Cost (M)
  2002.Maximum-Product-of-the-Length-of-Two-Palindromic-Subsequences (M)
  2151.Maximum-Good-People-Based-on-Statements (M+)
  2397.Maximum-Rows-Covered-by-Columns (M)
  • Meet in the Middle
    1755.Closest-Subsequence-Sum (H)
    2035.Partition-Array-Into-Two-Arrays-to-Minimize-Sum-Difference (H)

Divide and Conquer

315.Count-of-Smaller-Numbers-After-Self (H-)
327.Count-of-Range-Sum (H-)
493.Reverse-Pairs (M+)
1649.Create-Sorted-Array-through-Instructions (H)
2426.Number-of-Pairs-Satisfying-Inequality (H-)

String

006.ZigZag-Conversion (M+)
068.Text-Justification (H)
336.Palindrome-Pairs (H-)
388.Longest-Absolute-File-Path (M+)
418.Sentence-Screen-Fitting (M+)
423.Reconstruct-Original-Digits-from-English (H-)
616.Add-Bold-Tag-in-String (M)
467.Unique-Substrings-in-Wraparound-String (H-)
564.Find-the-Closest-Palindrome (H)
722.Remove-Comments (H)
736.Parse-Lisp-Expression (H-)
816.Ambiguous-Coordinates (M+)
844.Backspace-String-Compare (M+)
1616.Split-Two-Strings-to-Make-Palindrome (M+)
1754.Largest-Merge-Of-Two-Strings (M+)
1849.Splitting-a-String-Into-Descending-Consecutive-Values (M+)
2468.Split-Message-Based-on-Limit (H-)

• Abbreviation
  408.Valid-Word-Abbreviation (M)
  411.Minimum-Unique-Word-Abbreviation (H)
  527.Word-Abbreviation (M+)
  2060.Check-if-an-Original-String-Exists-Given-Two-Encoded-Strings (H)
• Rolling Hash
  1044.Longest-Duplicate-Substring (H)
  1062.Longest-Repeating-Substring (H-)
  1554.Strings-Differ-by-One-Character (H)
  1698.Number-of-Distinct-Substrings-in-a-String (H-)
  1923.Longest-Common-Subpath (H)
  2156.Find-Substring-With-Given-Hash-Value (M)
  2168.Unique-Substrings-With-Equal-Digit-Frequency (M+)
  2223.Sum-of-Scores-of-Built-Strings (H-)
  2261.K-Divisible-Elements-Subarrays (H-) 2781.Length-of-the-Longest-Valid-Substring (H-)
• KMP
  1392.Longest-Happy-Prefix (H)
  028.Implement-strStr (H)
  214.Shortest-Palindrome (H)
  459.Repeated-Substring-Pattern (H)
  572.Subtree-of-Another-Tree (H)
  1367.Linked-List-in-Binary-Tree (H)
  1397.Find All Good Strings (TBD)
  1764.Form-Array-by-Concatenating-Subarrays-of-Another-Array (H)
  2301.Match-Substring-After-Replacement (H-)
• Manacher
  005.Longest-Palindromic-Substring (H)
  214.Shortest-Palindrome (H)
  647.Palindromic-Substrings (M+)
  1960.Maximum-Product-of-the-Length-of-Two-Palindromic-Substrings (H)

Union Find

547.Friend-Circles (M)
200.Number-of-Islands (H-)
305.Number-of-Islands-II (H-)
130.Surrounded-Regions (H-)
128.Longest-Consecutive-Sequence (H-)
684.Redundant-Connection (M)
685.Redundant-Connection-II (H)
721.Accounts-Merge (M+)
765.Couples-Holding-Hands (H-)
785.Is-Graph-Bipartite (M+)
924.Minimize-Malware-Spread (H-)
947.Most-Stones-Removed-with-Same-Row-or-Column (M+)
959.Regions-Cut-By-Slashes (H-)
990.Satisfiability-of-Equality-Equations (M+)
1061.Lexicographically-Smallest-Equivalent-String (M)
1101.The-Earliest-Moment-When-Everyone-Become-Friends (M+)
1202.Smallest-String-With-Swaps (M+)
1319.Number-of-Operations-to-Make-Network-Connected (M+)
1632.Rank-Transform-of-a-Matrix (H)
1724.Checking-Existence-of-Edge-Length-Limited-Paths-II (H+)
1722.Minimize-Hamming-Distance-After-Swap-Operations (M+)
2076.Process-Restricted-Friend-Requests (H-)
2092.Find-All-People-With-Secret (H-)
2157.Groups-of-Strings (H)
2492.Minimum-Score-of-a-Path-Between-Two-Cities (M)

• Union in an order
  803.Bricks-Falling-When-Hit (H)
  1970.Last-Day-Where-You-Can-Still-Cross (H-)
  1631.Path-With-Minimum-Effort (H-)
  1697.Checking-Existence-of-Edge-Length-Limited-Paths (H-)
  2421.Number-of-Good-Paths (H)
• Prime Factors
  952.Largest-Component-Size-by-Common-Factor (H)
  1627.Graph-Connectivity-With-Threshold (M+)
  1998.GCD-Sort-of-an-Array (H-)
  2709.Greatest-Common-Divisor-Traversal (H-)
• MST
  1135.Connecting-Cities-With-Minimum-Cost　(M+)
  1168.Optimize-Water-Distribution-in-a-Village (H-)
  1489.Find-Critical-and-Pseudo-Critical-Edges-in-Minimum-Spanning-Tree (H)
  1579.Remove-Max-Number-of-Edges-to-Keep-Graph-Fully-Traversable (H-)
  1584.Min-Cost-to-Connect-All-Points (H-)

Recursion

087.Scramble-String (H-)
133.Clone-Graph (M+)
213.House-Robber-II (H-)
337.House-Robber-III (M+)
2646.Minimize-the-Total-Price-of-the-Trips (M+)
2378.Choose-Edges-to-Maximize-Score-in-a-Tree (H-)
390.Elimination-Game (H)
395.Longest-Substring-with-At-Least-K-Repeating-Characters (H)
397.Integer-Replacement (M+)
761.Special-Binary-String (H)
779.K-th-Symbol-in-Grammar (M)
780.Reaching-Points (H-)
808.Soup-Servings (H)
880.Decoded-String-at-Index (H-)
902.Numbers-At-Most-N-Given-Digit-Set (M)
964.Least-Operators-to-Express-Number (H)
991.Broken-Calculator (M)
1088.Confusing-Number-II (H)
1199.Minimum-Time-to-Build-Blocks (H+)
1274.Number-of-Ships-in-a-Rectangle (M)
1553.Minimum-Number-of-Days-to-Eat-N-Oranges (H)
1611.Minimum-One-Bit-Operations-to-Make-Integers-Zero (H)

• Evaluate Expressions
  241.Different-Ways-to-Add-Parentheses (M+)
  2019.The-Score-of-Students-Solving-Math-Expression (H-)
  679.24-Game (H)
• Min-Max Strategy
  464.Can-I-Win (M+)
  877.Stone-Game (M+) (aka. 486.Predict-the-Winner)
  1140.Stone-Game-II (M)
  1406.Stone-Game-III (M+)
  1510.Stone-Game-IV (M)
  1563.Stone-Game-V (H-)
  2029.Stone-Game-IX (H)
• Digit counting & finding
  440.K-th-Smallest-in-Lexicographical-Order (H-)
  1415.The-k-th-Lexicographical-String-of-All-Happy-Strings-of-Length-n (H-)
  1012.Numbers-With-Repeated-Digits (H-)
  1545.Find-Kth-Bit-in-Nth-Binary-String (TBD)
  2376.Count-Special-Integers (M+)
  2719.Count-of-Integers (H)

Graph

332.Reconstruct-Itinerary (H)
2097.Valid-Arrangement-of-Pairs (H)
753.Cracking-the-Safe (H)
1059.All-Paths-from-Source-Lead-to-Destination (H)
1192.Critical-Connections-in-a-Network (H)
1361.Validate-Binary-Tree-Nodes (TBD)
1719.Number-Of-Ways-To-Reconstruct-A-Tree (H+)
1761.Minimum-Degree-of-a-Connected-Trio-in-a-Graph (M+)
1782.Count-Pairs-Of-Nodes (H)
2360.Longest-Cycle-in-a-Graph (M+)
2508.Add-Edges-to-Make-Degrees-of-All-Nodes-Even (H-)
2556.Disconnect-Path-in-a-Binary-Matrix-by-at-Most-One-Flip (H)
2603.Collect-Coins-in-a-Tree (H-)
2608.Shortest-Cycle-in-a-Graph (M+)
2699.Modify-Graph-Edge-Weights (H)

• Floyd
  1334.Find-the-City-With-the-Smallest-Number-of-Neighbors-at-a-Threshold-Distance (M)
  2642.Design-Graph-With-Shortest-Path-Calculator (M+)
• Hungarian Algorithm
  1820.Maximum-Number-of-Accepted-Invitations (H)
  2123.Minimum-Operations-to-Remove-Adjacent-Ones-in-Matrix (H)

Math

089.Gray-Code (M+) (aka. 1238. Circular Permutation in Binary Representation)
458.Poor-Pigs (H)
400.n-th-digit (M)
441.Arranging-Coins (M-)
628.Maximum-Product-of-Three-Numbers (M)
672.Bulb-Switcher-II (H)
754.Reach-a-Number (H)
829.Consecutive-Numbers-Sum (M)
878.Nth-Magical-Number (M+)
883.Projection-Area-of-3D-Shapes (E+)
891.Sum-of-Subsequence-Widths (M+)
899.Orderly-Queue (M)
963.Minimum-Area-Rectangle-II (H-)
964.Least-Operators-to-Express-Number (H)
972.Equal-Rational-Numbers (H)
1017.Convert-to-Base--2 (M+)
1073.Adding-Two-Negabinary-Numbers (H-)
1025.Divisor-Game (M)
1040.Moving-Stones-Until-Consecutive-II (H)
1015.Smallest-Integer-Divisible-by-K (M+)
1103.Distribute-Candies-to-People (M+)
1330.Reverse-Subarray-To-Maximize-Array-Value (TBD)
1250.Check-If-It-Is-a-Good-Array (M+)
1680.Concatenation-of-Consecutive-Binary-Numbers (M)
1739.Building-Boxes (H-)
1806.Minimum-Number-of-Operations-to-Reinitialize-a-Permutation (H)
1969.Minimum-Non-Zero-Product-of-the-Array-Elements (M+)
2128.Remove-All-Ones-With-Row-and-Column-Flips (M+)
2217.Find-Palindrome-With-Fixed-Length (M+)

• Distances
  296.Best-Meeting-Point (M+)
  462.Minimum-Moves-to-Equal-Array-Elements-II (M-)
  2033.Minimum-Operations-to-Make-a-Uni-Value-Grid (M+)
  1703.Minimum-Adjacent-Swaps-for-K-Consecutive-Ones (H)
  1478.Allocate-Mailboxes (H)
  2448.Minimum-Cost-to-Make-Array-Equal (H-)
  1131.Maximum-of-Absolute-Value-Expression (H)
  1515.Best Position for a Service Centre (TBD)
  1956.Minimum-Time-For-K-Virus-Variants-to-Spread (H+)
  2607.Make-K-Subarray-Sums-Equal (M+)
• Geometry
  223.Rectangle-Area (M+)
  335.Self-Crossing (H)
  391.Perfect-Rectangle (H)
  587.Erect-the-Fence (H)
  593.Valid-Square (H)
  858.Mirror-Reflection (H)
  1401.Circle-and-Rectangle-Overlapping (H)
  1453.Maximum-Number-of-Darts-Inside-of-a-Circular-Dartboard (H)
  1610.Maximum-Number-of-Visible-Points (H)
  2280.Minimum-Lines-to-Represent-a-Line-Chart (M)
• Random Pick
  382.Linked-List-Random-Node (H)
  470.Implement-Rand10()-Using-Rand7() (M+)
  478.Generate-Random-Point-in-a-Circle (H-)
  497.Random-Point-in-Non-overlapping-Rectangles (M+)
  519.Random-Flip-Matrix (H-)
  528.Random-Pick-with-Weight (H-)
  710.Random-Pick-with-Blacklist (M+)
  1227.Airplane-Seat-Assignment-Probability (M+)
• Combinatorics
  046.Permutations (M+)
  047.Permutations-II (H)
  060.Permutation-Sequence (H)
  077.Combinations (H-)
  1286.Iterator-for-Combination (M+)
  1359.Count-All-Valid-Pickup-and-Delivery-Options (M+)
  1467.Probability-of-a-Two-Boxes-Having-The-Same-Number-of-Distinct-Balls (H-)
  1641.Count-Sorted-Vowel-Strings (M+)
  1643.Kth-Smallest-Instructions (M+)
  1735.Count-Ways-to-Make-Array-With-Product (H)
  1830.Minimum-Number-of-Operations-to-Make-String-Sorted (H)
  1866.Number-of-Ways-to-Rearrange-Sticks-With-K-Sticks-Visible (H)
  1916.Count-Ways-to-Build-Rooms-in-an-Ant-Colony (H)
  2221.Find-Triangular-Sum-of-an-Array (M)
  2400.Number-of-Ways-to-Reach-a-Position-After-Exactly-k-Steps (M+)
  2514.Count-Anagrams (H-)
• Numerical Theory
  204.Count-Primes (M)
  343.Integer-Break (H-)
  365.Water-and-Jug-Problem (H)
  1808.Maximize-Number-of-Nice-Divisors (H-)
  1819.Number-of-Different-Subsequences-GCDs (H-)
  2183.Count-Array-Pairs-Divisible-by-K (M+)
  2344.Minimum-Deletions-to-Make-Array-Divisible (E)
  2543.Check-if-Point-Is-Reachable (H)
  2654.Minimum-Number-of-Operations-to-Make-All-Array-Elements-Equal-to-1 (M)

Greedy

055.Jump-Game (E+)
045.Jump-Game-II (M)
134.Gas-Station (H)
229.Majority-Element-II (H)
659.Split-Array-into-Consecutive-Subsequences (H)
386.Lexicographical-Numbers (H)
624.Maximum-Distance-in-Arrays (M)
665.Non-decreasing-Array (H)
670.Maximum-Swap (M+)
649.Dota2-Senate (H)
330.Patching-Array (H)
683.K-Empty-Slots　(H)
517.Super-Washing-Machines (H)
870.Advantage-Shuffle (M)
781.Rabbits-in-Forest (M+)
881.Boats-to-Save-People (H-)
910.Smallest-Range-II (M+)
916.Word-Subsets (M+)
936.Stamping-The-Sequence (H)
948.Bag-of-Tokens (M+)
968.Binary-Tree-Cameras (H)
955.Delete-Columns-to-Make-Sorted-II (M+)
1040.Moving-Stones-Until-Consecutive-II (H)
1121.Divide Array Into Increasing Sequences (TBD)
1191.K-Concatenation-Maximum-Sum (M+)
1253.Reconstruct-a-2-Row-Binary-Matrix (M)
1354.Construct-Target-Array-With-Multiple-Sums (H-)
1414.Find-the-Minimum-Number-of-Fibonacci-Numbers-Whose-Sum-Is-K (M+)
1504.Count-Submatrices-With-All-Ones (M)
1505.Minimum-Possible-Integer-After-at-Most-K-Adjacent-Swaps-On-Digits (H)
1526.Minimum-Number-of-Increments-on-Subarrays-to-Form-a-Target-Array (H-)
1535.Find-the-Winner-of-an-Array-Game (M+)
1536.Minimum-Swaps-to-Arrange-a-Binary-Grid (H-)
1540.Can-Convert-String-in-K-Moves (M+)
1567.Maximum-Length-of-Subarray-With-Positive-Product (M+)
1578.Minimum-Deletion-Cost-to-Avoid-Repeating-Letters (M)
1585.Check-If-String-Is-Transformable-With-Substring-Sort-Operations (H)
1657.Determine-if-Two-Strings-Are-Close (M)
1702.Maximum-Binary-String-After-Change (H-)
1717.Maximum-Score-From-Removing-Substrings (M+)
1727.Largest-Submatrix-With-Rearrangements (M)
1744.Can-You-Eat-Your-Favorite-Candy-on-Your-Favorite-Day (M)
1788.Maximize-the-Beauty-of-the-Garden (M+)
1818.Minimum-Absolute-Sum-Difference (M+)
1850.Minimum-Adjacent-Swaps-to-Reach-the-Kth-Smallest-Number (M+)
1911.Maximum-Alternating-Subsequence-Sum (M+)
2086.Minimum-Number-of-Buckets-Required-to-Collect-Rainwater-from-Houses (M+)
2136.Earliest-Possible-Day-of-Full-Bloom (M+)
2170.Minimum-Operations-to-Make-the-Array-Alternating (M+)
2171.Removing-Minimum-Number-of-Magic-Beans (M)
2182.Construct-String-With-Repeat-Limit (M+)
2193.Minimum-Number-of-Moves-to-Make-Palindrome (H+)
2216.Minimum-Deletions-to-Make-Array-Beautiful (M+)
2242.Maximum-Score-of-a-Node-Sequence (M+)
2257.Count-Unguarded-Cells-in-the-Grid (M+)
2271.Maximum-White-Tiles-Covered-by-a-Carpet (M+)
2275.Largest-Combination-With-Bitwise-AND-Greater-Than-Zero (M+)
2306.Naming-a-Company (H-)
2311.Longest-Binary-Subsequence-Less-Than-or-Equal-to-K (H-)
2332.The-Latest-Time-to-Catch-a-Bus (H-)
2350.Shortest-Impossible-Sequence-of-Rolls (M+)
2365.Task-Scheduler-II (M)
2366.Minimum-Replacements-to-Sort-the-Array (H-)
2371.Minimize-Maximum-Value-in-a-Grid (M+)
2449.Minimum-Number-of-Operations-to-Make-Arrays-Similar (M+)
2457.Minimum-Addition-to-Make-Integer-Beautiful (M)
2546.Apply-Bitwise-Operations-to-Make-Strings-Equal (M+)
2551.Put-Marbles-in-Bags (M+)
2561.Rearranging-Fruits (H-)
2598.Smallest-Missing-Non-negative-Integer-After-Operations (M)

• Lexicographical Sequence
  031.Next-Permutation (M)
  556.Next-Greater-Element-III (M)
  2663.Lexicographically-Smallest-Beautiful-String (H-)
• DI Sequence
  942.DI-String-Match (M)
  484.Find-Permutation (M)
  2375.Construct-Smallest-Number-From-DI-String (M)
• Smear Top Elements
  2233.Maximum-Product-After-K-Increments (M+)
  2333.Minimum-Sum-of-Squared-Difference (M+)
  2234.Maximum-Total-Beauty-of-the-Gardens (H-)
• LIS
  300.Longest-Increasing-Subsequence (M+)
  354.Russian-Doll-Envelopes (H-)
  1713.Minimum-Operations-to-Make-a-Subsequence (H-)
  1964.Find-the-Longest-Valid-Obstacle-Course-at-Each-Position (M+)
  2111.Minimum-Operations-to-Make-the-Array-K-Increasing (M+)
• Two-pass distribution
  135.Candy (M+)
  1840.Maximum-Building-Height (H)
  1846.Maximum-Element-After-Decreasing-and-Rearranging (M+)
• Three-pass
  042.Trapping-Rain-Water (H-)
  334.Increasing-Triplet-Subsequence (H-)
  689.Maximum-Sum-of-3-Non-Overlapping-Subarrays (M+)
  907.Sum-of-Subarray-Minimums (H)
  1525.Number-of-Good-Ways-to-Split-a-String (M)
  1638.Count-Substrings-That-Differ-by-One-Character (M+)
  1653.Minimum-Deletions-to-Make-String-Balanced (M)
  1664.Ways-to-Make-a-Fair-Array (M)
  1671.Minimum-Number-of-Removals-to-Make-Mountain-Array (M+)
  1769.Minimum-Number-of-Operations-to-Move-All-Balls-to-Each-Box (M+)
  1888.Minimum-Number-of-Flips-to-Make-the-Binary-String-Alternating (M+)
  2163.Minimum-Difference-in-Sums-After-Removal-of-Elements (M+)
  2167.Minimum-Time-to-Remove-All-Cars-Containing-Illegal-Goods (H-)
  2555.Maximize-Win-From-Two-Segments (M+)
  2565.Subsequence-With-the-Minimum-Score (H-)
• State Machine
  524.Longest-Word-in-Dictionary-through-Deleting (M+)
  727.Minimum-Window-Subsequence (H-)
  792.Number-of-Matching-Subsequences (H-)
  1055.Shortest-Way-to-Form-String (M+)
  2055.Plates-Between-Candles (M+)
  2370.Longest-Ideal-Subsequence (M)
• Sort
  164.Maximum-Gap (H)
  179.Largest-Number (H-)
  581.shortest-unsorted-continuous-subarray (M+)
  275.H-Index-II (M+)
  406.Queue-Reconstruction-by-Height (M+)
  731.My-Calendar-II (M+)
  826.Most-Profit-Assigning-Work (M)
  1268.Search-Suggestions-System (H-)
  1402.Reducing-Dishes (M)
  1520.Maximum-Number-of-Non-Overlapping-Substrings (H-)
  1564.Put-Boxes-Into-the-Warehouse-I (M+)
  1665.Minimum-Initial-Energy-to-Finish-Tasks (H-)
  1686.Stone-Game-VI (H-)
  1996.The-Number-of-Weak-Characters-in-the-Game (M+)
  2250.Count-Number-of-Rectangles-Containing-Each-Point (H-)
  2343.Query-Kth-Smallest-Trimmed-Number (H-)
  2412.Minimum-Money-Required-Before-Transactions (H-)
  2345.Finding-the-Number-of-Visible-Mountains (H-)
• Indexing Sort
  041.First-Missing-Positive (H)
  268.Missing-Number (H-)
  287.Find-the-Duplicate-Number (H)
  442.Find-All-Duplicates-in-an-Array (M)
  448.Find-All-Numbers-Disappeared-in-an-Array (M)
  645.Set-Mismatch (M)
  2471.Minimum-Number-of-Operations-to-Sort-a-Binary-Tree-by-Level (M+)
  2459.Sort-Array-by-Moving-Items-to-Empty-Space (H)
• Parenthesis
  032.Longest-Valid-Parentheses (H)
  921.Minimum-Add-to-Make-Parentheses-Valid (M+)
  1249.Minimum-Remove-to-Make-Valid-Parentheses (M+)
  1541.Minimum-Insertions-to-Balance-a-Parentheses-String (M+)
  1963.minimum-number-of-swaps-to-make-the-string-balanced (M+)
  678.Valid-Parenthesis-String (H-)
  2116.Check-if-a-Parentheses-String-Can-Be-Valid (H-)
• Intervals
  435.Non-overlapping-Intervals (M+) (aka. 646.Maximum-Length-of-Pair-Chain)
  452.Minimum-Number-of-Arrows-to-Burst-Balloons (H-)
  757.Set-Intersection-Size-At-Least-Two (H)
  1024.Video-Stitching (M+)
  1272.Remove-Interval (M+)
  1288.Remove-Covered-Intervals (M+)
  1326.Minimum-Number-of-Taps-to-Open-to-Water-a-Garden (M+)
  1235.Maximum-Profit-in-Job-Scheduling (H-)
  1751.Maximum-Number-of-Events-That-Can-Be-Attended-II (H)
  2008.Maximum-Earnings-From-Taxi (M+)
  2054.Two-Best-Non-Overlapping-Events (H-)
  2580.Count-Ways-to-Group-Overlapping-Ranges (M)
  2589.Minimum-Time-to-Complete-All-Tasks (H)
• Constructive Problems
  324.Wiggle-Sort-II (H)
  667.Beautiful-Arrangement-II (M)
  932.Beautiful-Array (H)
  1605.Find-Valid-Matrix-Given-Row-and-Column-Sums (H-)
  2007.Find-Original-Array-From-Doubled-Array (M)
  2122.Recover-the-Original-Array (H-)
  1982.Find-Array-Given-Subset-Sums (H)
  2202.Maximize-the-Topmost-Element-After-K-Moves (H)
  2498.Frog-Jump-II (H)
  2499.minimum-total-cost-to-make-arrays-unequal (H)
  2567.Minimum-Score-by-Changing-Two-Elements (M)
  1798.Maximum-Number-of-Consecutive-Values-You-Can-Make (H-)
  2568.Minimum-Impossible-OR (H-)
  2571.Minimum-Operations-to-Reduce-an-Integer-to-0 (H-)
  2573.Find-the-String-with-LCP (H-)
  2576.Find-the-Maximum-Number-of-Marked-Indices (H-)
  2712.Minimum-Cost-to-Make-All-Characters-Equal (H-)
  2732.Find-a-Good-Subset-of-the-Matrix (H)
  2749.Minimum-Operations-to-Make-the-Integer-Zero (H)
  2745.Construct-the-Longest-New-String (H-)
  2753.Count-Houses-in-a-Circular-Street-II (H-)

Simulation

2061.Number-of-Spaces-Cleaning-Robot-Cleaned (M)
2069.Walking-Robot-Simulation-II (M+)
2532.Time-to-Cross-a-Bridge (H)

Others  

007.Reverse-Integer (M)
048.Rotate-Image (M+)
065.Valid-Number (H-)
158.Read-N-Characters-Given-Read4-II-Call-multiple-times　(H-)
240.Search-a-2D-Matrix-II (M+)
277.Find-the-Celebrity (H-)
311.Sparse-Matrix-Multiplication (M)
168.Excel-Sheet-Column-Title (H)
453.Minimum-Moves-to-Equal-Array-Elements (M)
782.Transform-to-Chessboard (H+)
466.Count-The-Repetitions (H)
810.Chalkboard-XOR-Game (H)
420.Strong-Password-Checker (H)
775.Global-and-Local-Inversions (M)
348.Design-Tic-Tac-Toe (M)
794.Valid-Tic-Tac-Toe-State (M+)
825.Friends-Of-Appropriate-Ages (M+)
835.Image-Overlap (H)
843.Guess-the-Word (M)
918.Maximum-Sum-Circular-Subarray (H-)
927.Three-Equal-Parts (M)
978.Longest-Turbulent-Subarray (H-)
1183.Maximum-Number-of-Ones (H)
1224.Maximum-Equal-Frequency (H) (aka. 2423. Remove Letter To Equalize Frequency)
1267.Count-Servers-that-Communicate (M+)
1538.Guess-the-Majority-in-a-Hidden-Array (M+)
1706.Where-Will-the-Ball-Fall (M+)
1749.Maximum-Absolute-Sum-of-Any-Subarray (M+)
1752.Check-if-Array-Is-Sorted-and-Rotated (M)
1826.Faulty-Sensor (M+)
1861.Rotating-the-Box (M)
1862.Sum-of-Floored-Pairs (M+)
1904.The-Number-of-Full-Rounds-You-Have-Played (M)
1997.First-Day-Where-You-Have-Been-in-All-the-Rooms (H)
2018.Check-if-Word-Can-Be-Placed-In-Crossword (M+)
2147.Number-of-Ways-to-Divide-a-Long-Corridor (M)
2337.Move-Pieces-to-Obtain-a-String (aka. 777.Swap-Adjacent-in-LR-String) (M+)
2359.Find-Closest-Node-to-Given-Two-Nodes (M)
2380.Time-Needed-to-Rearrange-a-Binary-String (H)
2453.Destroy-Sequential-Targets (M)
2591.Distribute-Money-to-Maximum-Children (M+)
2647.Color-the-Triangle-Red (H)
2718.Sum-of-Matrix-After-Queries (M+)

• Collision
  853.Car-Fleet (M)
  1503.Last-Moment-Before-All-Ants-Fall-Out-of-a-Plank (M)
  2211.Count-Collisions-on-a-Road (M)
  2731.Movement-of-Robots (M+)
• 结论转移
  1685.Sum-of-Absolute-Differences-in-a-Sorted-Array (M)
  2121.Intervals-Between-Identical-Elements (M)
  2615.Sum-of-Distances (M+)
• Count Subarray by Element
  828.Count-Unique-Characters-of-All-Substrings-of-a-Given-String (H-)
  907.Sum-of-Subarray-Minimums (H-)
  1498.Number-of-Subsequences-That-Satisfy-the-Given-Sum-Condition (H-)
  1856.Maximum-Subarray-Min-Product (M+)
  2104.Sum-of-Subarray-Ranges (H-)
  2262.Total-Appeal-of-A-String (M+)
  2281.Sum-of-Total-Strength-of-Wizards (H)
  2302.Count-Subarrays-With-Score-Less-Than-K (H-)
  2444.Count-Subarrays-With-Fixed-Bounds (M+)
  2681.Power-of-Heroes (H-)
  2763.Sum-of-Imbalance-Numbers-of-All-Subarrays (H-)
• 扫描线 / 差分数组
  252.Meeting-Rooms (M)
  253.Meeting-Rooms-II (M+)
  370.Range-Addition (H-)
  056.Merge-Intervals (M)
  057.Insert-Intervals (M)
  732.My-Calendar-III (M)
  759.Employee-Free-Time (M+)
  798.Smallest-Rotation-with-Highest-Score (H)
  995.Minimum-Number-of-K-Consecutive-Bit-Flips (H-)
  1094.Car-Pooling (E)
  1109.Corporate-Flight-Bookings (M)
  1589.Maximum-Sum-Obtained-of-Any-Permutation (M)
  1674.Minimum-Moves-to-Make-Array-Complementary (H)
  1871.Jump-Game-VII (M+)
  1893.Check-if-All-the-Integers-in-a-Range-Are-Covered (E)
  1943.Describe-the-Painting (H-)
  2015.Average-Height-of-Buildings-in-Each-Segment (H-)
  218.The-Skyline-Problem (H)
  2158.Amount-of-New-Area-Painted-Each-Day (H-)
  2237.Count-Positions-on-Street-With-Required-Brightness (M)
  2251.Number-of-Flowers-in-Full-Bloom (M)
  2327.Number-of-People-Aware-of-a-Secret (H-)
  2381.Shifting-Letters-II (M)
  2584.Split-the-Array-to-Make-Coprime-Products (H)
  2617.Minimum-Number-of-Visited-Cells-in-a-Grid (H)
  2772.Apply-Operations-to-Make-All-Array-Elements-Equal-to-Zero (H-)
• 二维差分
  850.Rectangle-Area-II (H)
  2132.Stamping-the-Grid (H)
  2536.Increment-Submatrices-by-One (H-)
• Enumeration
  479.Largest-Palindrome-Product (M+)
  866.Prime-Palindrome (H-)
  906.Super-Palindromes (H-)
  2081.Sum-of-k-Mirror-Numbers (H-)
  795.Number-of-Subarrays-with-Bounded-Maximum (M+)
  1625.Lexicographically-Smallest-String-After-Applying-Operations (H-)
  1714.Sum-Of-Special-Evenly-Spaced-Elements-In-Array (H)
  1737.Change-Minimum-Characters-to-Satisfy-One-of-Three-Conditions (M+)
  2013.Detect-Squares (M+)
  2552.Count-Increasing-Quadruplets (H-)
  2768.Number-of-Black-Blocks (M+)
• Presum
  1878.Get-Biggest-Three-Rhombus-Sums-in-a-Grid (M+)
  1906.Minimum-Absolute-Difference-Queries (M+)
  2245.Maximum-Trailing-Zeros-in-a-Cornered-Path (M)
  2281.Sum-of-Total-Strength-of-Wizards (H)
  2438.Range-Product-Queries-of-Powers (M+)
• 2D Presum
  1314.Matrix-Block-Sum (M)
  1292.Maximum-Side-Length-of-a-Square-with-Sum-Less-than-or-Equal-to-Threshold (H-)
  2132.Stamping-the-Grid (H)
• Quick Select
  215.Kth-Largest-Element-in-an-Array (M)
  347.Top-K-Frequent-Elements (M+)
  973.K-Closest-Points-to-Origin (M)
  324.Wiggle-Sort-II (H)
• 数位计算
  233.Number-of-Digit-One (H-)
  1067.Digit-Count-in-Range (H)
  357.Count-Numbers-with-Unique-Digits (M)
  1012.Numbers-With-Repeated-Digits (H-)
  2417.Closest-Fair-Integer (H-)

LeetCode Cup

LCP23.魔术排列
LCP24.数字游戏
LCP25.古董键盘
LCP32.批量处理任务
LCP35.电动车游城市
LCP36.最多牌组数
LCP43.十字路口的交通

Templates  

Math
Binary_Index_Tree
Segment Tree
Inverse_Element
Graph
Bit_Manipulation
RB_Tree
二维子矩阵求和
二维差分数组
CPP_LANG

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