Leetcode practice

Table of content

1. Problems
2. Interview
3. Weekly Contest
4. Biweekly Contest
5. Permutation - Combination - Subset
6. Tree
7. Queue & Stack
8. List
9. Dynamic Programming
10. Others

Problems

• 1. Two Sum (两数之和) - Array (数组), Hash Table (哈希表)
• 3. Longest Substring Without Repeating Characters (无重复字符的最长子串) - Sliding Window (滑动窗口)
• 5. Longest Palindromic Substring (最长回文子串) - Sliding Window (滑动窗口), Dynamic Programming (动态规划)
• 17. Letter Combinations of a Phone Number (电话号码的字母组合) - Backtracking (回溯)
• 19. Remove Nth Node From End of List (删除链表的倒数第 N 个结点) - Linked List (链表), Double Point (双指针)
• 21. Merge Two Sorted Lists (合并两个有序链表) - Linked List (链表), Recursive (递归)
• 23. Merge k Sorted Lists (合并K个升序链表) - Linked List (链表), Priority Queue (优先级队列)
• 26. Remove Duplicates from Sorted Array (删除有序数组中的重复项) - Array (数组), Double Point (双指针)
• 27. Remove Element (移除元素) - Array (数组), Double Point (双指针)
• 35. Search Insert Position (搜索插入位置) - Binary Search (二分查找)
• 36. Valid Sudoku (有效的数独) - Array (数组), Hash Table (哈希表), Matrix (矩阵)
• 37. Sudoku Solver (解数独) - Array (数组), Backtracking (回溯), Matrix (矩阵)
• 39. Combination Sum (组合总和) - Backtracking (回溯)
• 40. Combination Sum II (组合总和 II) - Backtracking (回溯)
• 46. Permutations (全排列) - Backtracking (回溯)
• 47. Permutations II (全排列 II) - Backtracking (回溯)
• 51. N-Queens (N 皇后) - Backtracking (回溯)
• 64. Minimum Path Sum (最小路径和) - Dynamic Programming (动态规划)
• 70. Climbing Stairs (爬楼梯) - Dynamic Programming (动态规划)
• 77. Combinations (组合) - Backtracking (回溯)
• 78. Subsets (子集) - Backtracking (回溯)
• 83. Remove Duplicates from Sorted List (删除排序链表中的重复元素) - Linked List (链表), Double Point (双指针)
• 86. Partition List (分隔链表) - Linked List (链表), Double Point (双指针)
• 90. Subsets ii (子集 II) - Backtracking (回溯)
• 92. Reverse Linked List II (反转链表 II) - Linked List (链表)
• 94. Binary Tree Inorder Traversal (二叉树的中序遍历) - Binary Tree (二叉树), Inorder (中序遍历), DFS (深度优先搜索)
• 98. Validate Binary Search Tree (验证二叉搜索树) - Binary Tree (二叉树), Binary Search Tree (二叉搜索树), Inorder (中序遍历)
• 102. Binary Tree Level Order Traversal (二叉树的层序遍历) - Binary Tree (二叉树), Level order (层序遍历), BFS (广度优先搜索)
• 104. Maximum Depth of Binary Tree (二叉树的最大深度) - Binary Tree (二叉树), BFS (广度优先搜索), DFS (深度优先搜索), Backtracking (回溯)
• 108. Convert Sorted Array to Binary Search Tree (将有序数组转换为二叉搜索树) - Binary Tree (二叉树), Binary Search Tree (二叉搜索树)
• 110. Balanced Binary Tree (平衡二叉树) - Binary Tree (二叉树)
• 116. Populating Next Right Pointers in Each Node (填充每个节点的下一个右侧节点指针) - BFS (广度优先搜索), DFS (深度优先搜索)
• 121. Best Time to Buy and Sell Stock (买卖股票的最佳时机) - Array (数组), Dynamic Programming (动态规划)
• 122. Best Time to Buy and Sell Stock II (买卖股票的最佳时机 II) - Dynamic Programming (动态规划), Greedy (贪心)
• 123. Best Time to Buy and Sell Stock III (买卖股票的最佳时机 III) - Array (数组), Dynamic Programming (动态规划)
• 136. Single Number (只出现一次的数字) - Array (数组), Bit Manipulation (位运算)
• 141. Linked List Cycle (环形链表) - Linked List (链表), Double Point (双指针)
• 142. Linked List Cycle II (环形链表 II) - Linked List (链表), Double Point (双指针), Hash Table (哈希表)
• 144. Binary Tree Preorder Traversal (二叉树的前序遍历) - Binary Tree (二叉树), Preorder (前序遍历), DFS (深度优先搜索)
• 145. Binary Tree Postorder Traversal (二叉树的后序遍历) - Binary Tree (二叉树), Postorder (后序遍历), DFS (深度优先搜索)
• 160. Intersection of Two Linked Lists (相交链表) - Linked List (链表), Hash Table (哈希表)
• 167. Two Sum II - Input Array Is Sorted (两数之和 II - 输入有序数组) - Array (数组), Double Point (双指针)
• 173. Binary Search Tree Iterator (二叉搜索树迭代器) - Binary Tree (二叉树), Binary Search Tree (二叉搜索树), Inorder (中序遍历)
• 188. Best Time to Buy and Sell Stock IV (买卖股票的最佳时机 IV) - Array (数组), Dynamic Programming (动态规划)
• 189. Rotate Array (轮转数组) - Array (数组), Double Point (双指针)
• 206. Reverse Linked List (反转链表) - Double Point (双指针), Recursive (递归)
• 216. Combination Sum III (组合总和 III) - Backtracking (回溯)
• 217. Contains Duplicate (存在重复元素) - Hash Table (哈希表)
• 220. Contains Duplicate III (存在重复元素 III) - Binary Tree (二叉树), Binary Search Tree (二叉搜索树)
• 235. Lowest Common Ancestor of a Binary Search Tree (二叉搜索树的最近公共祖先) - Binary Tree (二叉树), Binary Search Tree (二叉搜索树), DFS (深度优先搜索)
• 278. First Bad Version (第一个错误的版本) - Binary Search (二分查找)
• 283. Move Zeroes (移动零) - Array (数组), Double Point (双指针)
• 309. Best Time to Buy and Sell Stock with Cool down (最佳买卖股票时机含冷冻期) - Array (数组), Dynamic Programming (动态规划)
• 344. Reverse String (反转字符串) - Double Point (双指针)
• 349. Intersection of Two Arrays (两个数组的交集) - Array (数组), Double Point (双指针)
• 350. Intersection of Two Arrays II (两个数组的交集 II) - Array (数组), Double Point (双指针), Hash Table (哈希表)
• 450. Delete Node in a BST (删除二叉搜索树中的节点) - Binary Tree (二叉树), Binary Search Tree (二叉搜索树)
• 491. Increasing Subsequences (递增子序列) - Backtracking (回溯), Hash Table (哈希表)
• 542. 01 Matrix (01 矩阵) - BFS (广度优先搜索), Dynamic Programming (动态规划)
• 557. Reverse Words in a String III (反转字符串中的单词 III) - String (字符串)
• 567. Permutation in String (字符串的排列) - Sliding Window (滑动窗口)
• 617. Merge Two Binary Trees (合并二叉树) - DFS (深度优先搜索)
• 695. Max Area of Island (岛屿的最大面积) - DFS (深度优先搜索)
• 700. Search in a Binary Search Tree (二叉搜索树中的搜索) - Binary Tree (二叉树), Binary Search Tree (二叉搜索树), Recursive (递归)
• 701. Insert into a Binary Search Tree (二叉搜索树中的插入操作) - Binary Tree (二叉树), Binary Search Tree (二叉搜索树), Recursive (递归)
• 703. Kth Largest Element in a Stream (数据流中的第 K 大元素) - Binary Tree (二叉树), Binary Search Tree (二叉搜索树)
• 704. Binary Search (二分查找) - Binary Search (二分查找)
• 733. Flood Fill (图像渲染) - DFS (深度优先搜索)
• 784. Letter case permutation (字母大小写全排列) - BFS (广度优先搜索), Backtracking (回溯)
• 876. Middle of the Linked List (链表的中间结点) - Linked List (链表), Double Point (双指针)
• 977. Squares of a Sorted Array (有序数组的平方) - Double Point (双指针)
• 994. Rotting Oranges (腐烂的橘子) - BFS (广度优先搜索)
• 1732. Find the Highest Altitude (找到最高海拔) - Prefix Sum (前缀和)

Interview

• 08.01. Three steps problem (三步问题) - Dynamic Programming (动态规划)

Weekly Contest

321. 2022-11-27

• 6245. Find the pivot integer (找出中枢整数)
• 6246. Append characters to string to make subsequence (追加字符以获得子序列)
• 6247. Remove nodes from linked list (从链表中移除节点)

322. 2022-12-04

• 6253. Circular sentence (回环句)
• 6254. Divide players into teams of equal skill (划分技能点相等的团队)

323. 2022-12-11

• 6257. Delete Greatest Value in Each Row (删除每行中的最大值)
• 6258. Longest Square Streak in an Array (数组中最长的方波)
• 6259. Design Memory Allocator (设计内存分配器)

324. 2022-12-18

• 6265. Count Pairs Of Similar Strings (统计相似字符串对的数目)
• 6266. Smallest Value After Replacing With Sum of Prime Factors (使用质因数之和替换后可以取到的最小值)

325. 2022-12-25

• 6269. Shortest Distance to Target String in a Circular Array (到目标字符串的最短距离)

327. 2023-01-08

• 6283. Maximum Count of Positive Integer and Negative Integer (正整数和负整数的最大计数)
• 6285. Maximal Score After Applying K Operations (执行 K 次操作后的最大分数)

328. 2023-01-15

• 6291. Difference Between Element Sum and Digit Sum of an Array (数组元素和与数字和的绝对差)
• 6292. Increment SubMatrices by One (子矩阵元素加 1)

329. 2023-01-22

• 2544. Alternating Digit Sum (交替数字和)
• 2545. Sort the Students by Their Kth Score (根据第 K 场考试的分数排序)
• 2546. Apply Bitwise Operations to Make Strings Equal (执行逐位运算使字符串相等)

331. 2023-02-05

• 6348. Take Gifts From the Richest Pile (从数量最多的堆取走礼物)
• 6347. Count Vowel Strings in Ranges (统计范围内的元音字符串数)
• 2560. House Robber IV (打家劫舍 IV)

332. 2023-02-12

• 6354. Find the Array Concatenation Value (找出数组的串联值)
• 6355. Count the Number of Fair Pairs (统计公平数对的数目)

334. 2023-02-26

• 6369. Left and Right Sum Differences (左右元素和的差值)
• 6368. Find the Divisibility Array of a String (找出字符串的可整除数组)
• 2576. Find the Maximum Number of Marked Indices (求出最多标记下标)

336. 2023-03-12

• 6315. Count the Number of Vowel Strings in Range (统计范围内的元音字符串数)
• 6316. Rearrange Array to Maximize Prefix Score (重排数组以得到最大前缀分数)
• 6317. Count the Number of Beautiful Subarrays (统计美丽子数组数目)

337. 2023-03-19

• 6319. Number of Even and Odd Bits (奇偶位数)
• 6322. Check Knight Tour Configuration (检查骑士巡视方案)
• 6352. The Number of Beautiful Subsets (美丽子集的数目)

Biweekly Contest

92. 2022-11-26

• 6249. Minimum cuts to divide a circle (分割圆的最少切割次数)
• 6250. Minimum penalty for a shop (商店的最少代价)
• 6277. Difference between ones and zeros in row and column (行和列中一和零的差值)

93. 2022-12-10

• 6261. Maximum Value of a String in an Array (数组中字符串的最大值)
• 6262. Maximum Star Sum of a Graph (图中最大星和)
• 6263. Frog Jump II (青蛙过河 II)

94. 2022-12-24

• 6273. Maximum Enemy Forts That Can Be Captured (最多可以摧毁的敌人城堡数目)
• 6274. Reward Top K Students (奖励最顶尖的 K 名学生)

95. 2023-01-07

• 6287. Categorize Box According to Criteria (根据规则将箱子分类)
• 6288. Find Consecutive Integers from a Data Stream (找到数据流中的连续整数)
• 6289. Find Xor-Beauty of Array (查询数组 Xor 美丽值)

96. 2023-01-21

• 2540. Minimum Common Value (最小公共值)

97. 2023-02-04

• 6303. Separate the Digits in an Array (分割数组中数字的数位)
• 6304. Maximum Number of Integers to Choose From a Range I (从一个范围内选择最多整数 I)

98. 2023-02-18

• 6359. Maximum Difference by Remapping a Digit (替换一个数字后的最大差值)
• 6361. Minimum Score by Changing Two Elements (修改两个元素的最小分数)

99. 2023-03-04

• 6312. Split With Minimum Sum (最小和分割)
• 6311. Count Total Number of Colored Cells (统计染色格子数)

100. 2023-03-18

• 6323. Distribute Money to Maximum Children (将钱分给最多的儿童)
• 6324. Maximize Greatness of an Array (最大化数组的伟大值)

Permutation - Combination - Subset

Permutation 排列

• 46. Permutations (全排列) - Backtracking (回溯)
• 47. Permutations II (全排列 II) - Backtracking (回溯)

Combination 组合

• 17. Letter Combinations of a Phone Number (电话号码的字母组合) - Backtracking (回溯)
• 39. Combination Sum (组合总和) - Backtracking (回溯)
• 40. Combination Sum II (组合总和 II) - Backtracking (回溯)
• 216. Combination Sum III (组合总和 III) - Backtracking (回溯)
• 77. Combinations (组合) - Backtracking (回溯)

Subset 子集

• 78. Subsets (子集) - Backtracking (回溯)
• 90. Subsets ii (子集 II) - Backtracking (回溯)

Tree

94.binary-tree-inorder-traversal (二叉树的中序遍历)

• recursion
• iteration
• iteration-not-change-tree
• morris

101.symmetric-tree (对称二叉树)

• 101.symmetric-tree.c

102.binary-tree-level-order-traversal (二叉树的层序遍历)

• recursion
• iteration
• 102.binary-tree-level-order-traversal.cpp

104.maximum-depth-of-binary-tree (二叉树的最大深度)

• bottom-up
• top-down

105.construct-binary-tree-from-preorder-and-inorder-traversal (从前序与中序遍历序列构造二叉树)

• 105.construct-binary-tree-from-preorder-and-inorder-traversal.c

106.construct-binary-tree-from-inorder-and-postorder-traversal (从中序与后序遍历序列构造二叉树)

• 106.construct-binary-tree-from-inorder-and-postorder-traversal.c

112.path-sum (路径总和)

• 112.path-sum.c

116.populating-next-right-pointers-in-each-node (填充每个节点的下一个右侧节点指针)

• 116.populating-next-right-pointers-in-each-node.c
• faster

117.populating-next-right-pointers-in-each-node-ii (填充每个节点的下一个右侧节点指针 II)

• 117.populating-next-right-pointers-in-each-node-ii.c
• 117.populating-next-right-pointers-in-each-node-ii-slow.cpp
• 117.populating-next-right-pointers-in-each-node-ii.cpp

144.binary-tree-preorder-traversal (二叉树的前序遍历)

• recursion
• iteration
• morris

145.binary-tree-postorder-traversal (二叉树的后序遍历)

• recursion
• iteration
• morris

236.lowest-common-ancestor-of-a-binary-tree (二叉树的最近公共祖先)

• 236.lowest-common-ancestor-of-a-binary-tree.cpp

297.serialize-and-deserialize-binary-tree (二叉树的序列化与反序列化)

• 297.serialize-and-deserialize-binary-tree.c
• 297.serialize-and-deserialize-binary-tree.cpp

Queue & Stack

622.design-circular-queue (设计循环队列)

• 622.design-circular-queue.c

200.number-of-islands (岛屿数量)

• dfs
• bfs
• union find (并查集)

130.surrounded-regions (被围绕的区域)

• dfs
• union find (并查集)

752.open-the-lock (打开转盘锁)

• 752.open-the-lock.c

279.perfect-squares (完全平方数)

• recursion
• bfs
• dynamic programming
• greedy enum (贪心枚举)
• greedy bfs
• math (four-square and three-square theorems) (四平方三平方定理)

List

206.reverse-linked-list (反转链表)

• recursion
• iteration

92.reverse-linked-list-ii (反转链表 II)

• recursion
• iteration

876.middle-of-the-linked-list (链表的中间结点)

• recursion
• iteration
• slow-fast-pointers

Dynamic Programming

• _0070ClimbingStairs
• _0064MinimumPathSum
• Interview0801ThreeStepsProblem

Others

1.two-sum (两数之和)

• 1.two-sum.c
• _0001TwoSum.java

36.valid-sudoku (有效的数独)

• _0036ValidSudoku.java

37.sudoku-solver (解数独)

• _0037SudokuSolver.java

1323.maximum-69-number (6 和 9 组成的最大数字)

• 1323.maximum-69-number.c

1732.find-the-highest-altitude (找到最高海拔)

• 1732.find-the-highest-altitude.java

557.reverse-words-in-a-string-iii (反转字符串中的单词 iii)

• _0577ReverseWordsInAStringiii.java

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