Merge sort is most common for interviews Bucket sort or quicksort is next.
Two Sum (#1) Single Number (#136) Furthest Building You Can Reach (#1642) Next Greater Element II (#503) Sort Colors (#75) Majority Element (#169) Heap:
Kth Largest Element in a Stream (#703) Top K Frequent Elements (#347) BFS:
Rotting Oranges (#994) Binary Tree Level Order Traversal (#102) DFS:
Symmetric Tree (#101) Binary Tree Right Side View (#199) Linked List:
Remove Nth Node From End of List (#19) Merge Two Sorted Lists (#21) Linked List Cycle (#141) Intersection of Two Linked Lists (#160) Trees:
Validate Binary Search Tree (#98) Lowest Common Ancestor of a Binary Search Tree (#235) Diameter of Binary Tree (#543) Serialize and Deserialize Binary Tree (#297) Strings:
Valid Anagram (#242) Palindromic Substrings (#647) Longest Common Subsequence (#1143) Dynamic Programming:
Shortest Common Supersequence (#1092) Longest Common Subsequence (#1143) Medium Priority: Arrays:
Trapping Rain Water (#42) Trapping Rain Water II (#407) Count of Smaller Numbers After Self (#315) Linked List:
Reverse Linked List (#206) Trees:
Lowest Common Ancestor of a Binary Tree (#236) Binary Tree Inorder Traversal (#94) Binary Tree Zigzag Level Order Traversal (#103) Strings:
Longest Palindromic Substring (#5) Implement strStr() (#28) Heap:
Kth Largest Element in an Array (#215) Bit Manipulation:
Number of 1 Bits (#191) Maximum XOR of Two Numbers in an Array (#421) Single Number II (#137) Low Priority: Arrays:
Find the Duplicate Number (#287) Find All Duplicates in an Array (#442) Strings:
Longest Substring Without Repeating Characters (#3) Dynamic Programming:
Jump Game (#55) Heap:
Find Median from Data Stream (#295) Linked List:
Clone Linked List with Random Pointer (#138)