leetcode 刷题

150to200/最大数.py

@@ -0,0 +1,14 @@
+from typing import List
+
+
+class Solution:
+    def largestNumber(self, nums: List[int]) -> str:
+
+        for i in range(len(nums) - 1):
+            for j in range(i + 1, len(nums)):
+                if str(nums[i]) + str(nums[j]) < str(nums[j]) + str(nums[i]):
+                    nums[i], nums[j] = nums[j], nums[i]
+        s = ""
+        for num in nums:
+            s += str(num)
+        return str(int(s))

1to50/K 个一组翻转链表.py

@@ -0,0 +1,33 @@
+# Definition for singly-linked list.
+from typing import Optional
+class ListNode:
+    def __init__(self, val=0, next=None):
+        self.val = val
+        self.next = next
+
+
+class Solution:
+    def reverseKGroup(self, head: Optional[ListNode], k: int) -> Optional[ListNode]:
+        dummy = ListNode()
+        p = dummy
+        while True:
+            count = k
+            stack = []
+            tmp = head
+            while count and tmp:
+                stack.append(tmp)
+                tmp = tmp.next
+                count -= 1
+            if count:
+                p.next = head
+                break
+            while stack:
+                p.next = stack.pop()
+                p = p.next
+            p.next = tmp
+            head = tmp
+        return dummy.next
+
+
+if __name__ == '__main__':
+    print(Solution().reverseKGroup([1, 2, 3, 4, 5], 2))

1to50/三数之和.py

@@ -0,0 +1,20 @@
+from itertools import combinations
+from typing import List
+
+
+class Solution:
+    def threeSum(self, nums: List[int]) -> List[List[int]]:
+        L = []
+        for i in combinations(nums, 3):
+            if sum(list(i)) == 0:
+                L.append(list(i))
+        L1 = []
+        for j in L:
+            j.sort()
+            L1.append(j)
+        b = list(set([tuple(j) for j in L1]))
+        return [list(i) for i in b]
+
+
+nums = [-1, 0, 1, 2, -1, -4]
+print(Solution().threeSum(nums))

1to50/两两交换链表中的节点.py

@@ -0,0 +1,14 @@
+# Definition for singly-linked list.
+# class ListNode:
+#     def __init__(self, val=0, next=None):
+#         self.val = val
+#         self.next = next
+class Solution:
+    def swapPairs(self, head: Optional[ListNode]) -> Optional[ListNode]:
+        if not head or not head.next:
+            return head
+
+        tail = head.next
+        head.next = self.swapPairs(tail.next)
+        tail.next = head
+        return tail

1to50/两数之和.py

@@ -0,0 +1,22 @@
+from typing import List
+
+
+class Solution:
+
+    @staticmethod
+    def twoSum(nums: List[int], target: int) -> List[int]:
+        length = len(nums)
+        if length < 2:
+            return []
+        for k, v in enumerate(nums):
+
+            for j in range(k + 1, length):
+                if v + nums[j] == target:
+                    return [k, j]
+        return []
+
+
+if __name__ == '__main__':
+    nums = [3, 2, 4]
+    target = 6
+    print(Solution.twoSum(nums, target))

1to50/两数相加.py

@@ -0,0 +1,19 @@
+# Definition for singly-linked list.
+
+from typing import Optional
+
+
+class ListNode:
+    def __init__(self, val=0, next=None):
+        self.val = val
+        self.next = next
+
+
+class Solution:
+    def addTwoNumbers(self, l1, l2) -> Optional[ListNode]:
+        l1.val += l2.val
+        if l1.val > 10:
+            l1.next = self.addTwoNumbers(ListNode(l1.val // 10), l1.next)
+            l1.val %= 10
+        l1.next = self.addTwoNumbers(l1.next, l2.next)
+        return l1

1to50/冒泡排序.py

@@ -0,0 +1,7 @@
+def bubbleSort(data: list):
+    length = len(data)
+    for i in range(length - 1):
+        for j in range(length - i - 1):
+            if data[j] > data[j + 1]:
+                data[j], data[j + 1] = data[j + 1], data[j]
+    return data

1to50/去除水印.py

@@ -0,0 +1,16 @@
+from PyPDF2 import PdfReader, PdfWriter
+
+output = PdfWriter()
+
+reader = PdfReader(r"D:\CU_76a18490a1c94c20bda9ccfc81acabd6 (1).pdf")
+# 获取总页数
+page_count = reader.getNumPages()
+
+# with open(,'rb') as pf:
+#     pin = PdfReader(pf)
+#     for i in range(2):
+#         page = pin.getPage(pin.pages[0])
+#         print(page)
+#     #     output.addPage(page)
+#     # with open("XXXX/out.pdf",'wb') as ouf:
+#     #     output.write(ouf)

1to50/合并K个升序链表.py

@@ -0,0 +1,24 @@
+# Definition for singly-linked list.
+class ListNode:
+    def __init__(self, val=0, next=None):
+        self.val = val
+        self.next = next
+
+
+class Solution:
+    def mergeKLists(self, lists: List[Optional[ListNode]]) -> Optional[ListNode]:
+        heap = []
+        for sub_list in lists:
+            while sub_list:
+                heap.append(sub_list.val)
+                sub_list = sub_list.next
+        heap.sort(reverse=True)
+
+        head = ListNode(None)
+        curr_list = head
+        while heap:
+            # 从heap列表的尾部取最小数加入到链表中
+            temp_list = ListNode(heap.pop())
+            curr_list.next = temp_list
+            curr_list = curr_list.next
+        return head.next

1to50/回文数.py

@@ -0,0 +1,13 @@
+class Solution:
+    def isPalindrome(self, x: int) -> bool:
+        if x < 0:
+            return False
+        x1 = str(x)[::-1]
+        if int(x1) == x:
+            return True
+        return False
+
+
+if __name__ == '__main__':
+    x = -123
+    print(str(x)[::-1].isalnum())

1to50/字符串转换整数 (atoi).py

@@ -0,0 +1,12 @@
+import re
+
+
+class Solution:
+    def myAtoi(self, s: str) -> int:
+        INT_MAX = 2147483647
+        INT_MIN = -2147483648
+        str = s.lstrip()  # 清除左边多余的空格
+        num_re = re.compile(r'^[\+\-]?\d+')  # 设置正则规则
+        num = num_re.findall(str)  # 查找匹配的内容
+        num = int(*num)  # 由于返回的是个列表，解包并且转换成整数
+        return max(min(num, INT_MAX), INT_MIN)  # 返回值