/leetcode

My Leetcode Solutions

Primary LanguageJava

Leetcode Notes

# Title Solution Tag Difficulty Significance
1 Two Sum JAVA 哈希 Easy ♥
2 Add Two Numbers JAVA 链表 Median ♥
3 Longest Substring Without Repeating Character JAVA 滑动窗口 Median ♥♥♥
4 Median of Two Sorted Arrays JAVA Hard
5 Longest Palindromic Substring JAVA 中心扩展
动态规划		 Median ♥♥
6 ZigZag Conversion JAVA Median
7 Reverse Integer JAVA Easy
8 String to Integer (atoi) JAVA Median
9 Palindrome Number JAVA 回文数 Easy
10 Regular Expression Matching JAVA Hard
11 Container With Most Water JAVA Median
12 Integer to Roman JAVA Median
13 Roman to Integer JAVA Easy
14 Longest Common Prefix JAVA Easy
15 3Sum JAVA Median
16 3Sum Closest JAVA Median
17 Letter Combinations of a Phone Number JAVA Median
18 4Sum JAVA Median
19 Remove Nth Node From End of List JAVA Median
20 Valid Parentheses JAVA Easy
21 Merge Two Sorted Lists JAVA Easy
22 Generate Parentheses JAVA Median
23 Merge k Sorted Lists JAVA 堆
分治		 Hard ♥
24 Swap Nodes in Pairs JAVA Median
25 Reverse Nodes in k-Group JAVA Hard
26 Remove Duplicates from Sorted Array JAVA Easy
27 Remove Element JAVA Easy
28 Implement strStr() JAVA KMP算法 Easy ♥
29 Divide Two Integers JAVA Median
30 Substring with Concatenation of All Words JAVA Hard
31 Next Permutation JAVA 数学分析 Median ♥
32 Longest Valid Parentheses JAVA Hard
33 Search in Rotated Sorted Array JAVA Median
34 Find First and Last Position of Element JAVA 二分查找 Median ♥ ♥
35 Search Insert Position JAVA 二分查找 Easy ♥♥
36 Valid Sudoku JAVA Median
37 Sudoku Solver JAVA Hard
38 Count and Say JAVA Easy
39 Combination Sum JAVA 回溯法 Median ♥
40 Combination Sum II JAVA 回溯
剪枝		 Medium ♥♥
42 Trapping Rain Water JAVA 从列入手
动态规划
双指针		 Hard ♥♥♥
43 Multiply Strings JAVA 字符串 Medium ♥
46 Permutations JAVA 全排列
回溯		 Medium ♥♥
47 PermutationsII JAVA 全排列
回溯		 Medium ♥
49 Group Anagrams JAVA 哈希 Medium ♥
50 Pow(x, n) JAVA 分治 Medium ♥
51 N-Queens JAVA 回溯 Hard ♥
53 Maximum Subarray JAVA 动态规划
线段树		 Easy ♥♥
54 Spiral Matrix JAVA 数组 Medium ♥
55 Jump Game JAVA 贪心 Medium ♥
56 Merge Intervals JAVA 区间合并
排序		 Median ♥♥
57 Insert Interval JAVA 区间合并
排序		 Hard ♥♥
58 Length Of Last Word JAVA 字符串 Easy
59 Spiral Matrix II JAVA 模拟题 Medium ♥
60 Permutation Sequence JAVA DFS Medium ♥
61 Rotate List JAVA LinkedList Medium
63 Unique Path II JAVA 动态规划 Medium
64 Minimum Path Sum JAVA 动态规划 Medium
66 Plus One JAVA 数组 Easy ♥
67 Add Binary JAVA 字符串 Easy
69 Sqrt(x) JAVA 二分查找
牛顿迭代		 Easy ♥
70 Climbing Stairs JAVA 动态规划 Easy
72 Edit Distance JAVA 动态规划 Hard ♥♥
74 Search a 2D Matrix JAVA 二分查找 Medium ♥
75 Sort Colors JAVA 计数排序 Easy ♥
76 Minimum Window Substring JAVA 滑动窗口 Hard ♥ ♥
78 Subsets JAVA 递归 Medium ♥
79 Word Search JAVA 回溯 Medium ♥
80 Remove Duplicates From SA II JAVA 数组
双指针		 Medium ♥
81 Search in Rotated Array II JAVA 二分查找 Medium ♥
82 Remove Duplicates From SL II JAVA 链表 Medium ♥
83 Remove Duplicates From SL JAVA 链表 Easy
84 Largest Rectangle Histogram JAVA 单调栈 Hard ♥♥
86 Partition List JAVA 链表 Medium ♥
88 Merge Sorted Array JAVA 数组 Easy
90 Subsets II JAVA 回溯
组合		 Medium ♥
92 Reverse Linked List II JAVA 链表 Medium ♥
93 Restore IP Address JAVA 回溯？ Medium ♥
94 Binary Tree Inorder Traversal JAVA 二叉树
中序遍历		 Medium ♥♥
95 Unique Binary Search Trees II JAVA 二叉搜索
递归		 Median ♥♥
96 Unique Binary Search Trees JAVA 二叉搜索
动态规划		 Median ♥
98 Validate Binary Search Tree JAVA 二叉搜索 Median ♥
99 Recover Binary Search Tree JAVA 二叉搜索 Hard ♥♥
101 Symmetric Tree JAVA 二叉树
对称		 Easy ♥
102 Binary Tree Level Order Traversal JAVA 二叉树
层序遍历		 Medium ♥
103 Binary Tree Zigzag Level Order Traversal JAVA 二叉树
层序		 Medium ♥
104 Maximum Depth of Binary Tree JAVA 二叉树
最大深度		 Easy
105 Construct Binary Tree from P and I JAVA 构建
二叉树		 Median ♥
106 Construct Binary Tree from I and P JAVA 构建
二叉树		 Median ♥
107 Binary Tree Level Order Traversal II JAVA 二叉树
层序遍历		 Medium
108 Converted Sorted Array to BST JAVA 二叉树
递归		 Easy
110 Balanced Binary Tree JAVA 平衡二叉 Easy? ♥
111 Minimum Depth of Binary Tree JAVA 二叉树
最小深度		 Easy
112 Path Sum JAVA 二叉树 Easy
113 Path Sum II JAVA 二叉树 Medium ♥
114 Flatten Binary Tree to Linked List JAVA 二叉树 Medium ♥♥
116 Populating Next Right Pointers JAVA 二叉树
 Median
117 Populating Next Right Pointers II JAVA 二叉树
 Median
118 Pascal's Triangle JAVA Easy 迭代
121 Best Time to BAS Stock JAVA 贪心 Easy
122 Best Time to BAS Stock II JAVA 动态规划 Easy ♥♥
123 Best Time To BAS Stock III JAVA 动态规划 Hard ♥♥
124 Binary Tree Maximum Path Sum JAVA 二叉树
递归		 Hard ♥♥♥
127 Word Ladder JAVA BFS Medium ♥♥
128 Longest Consecutive Sequence JAVA 哈希 Medium ♥♥
129 Sum Root to Leaf Numbers JAVA 二叉树
前序遍历		 Medium
131 Palindrome Partitioning JAVA 动态规划
回溯		 Medium ♥♥
132 Palindrome Partitioning II JAVA 动态规划 Hard ♥♥
134 Gas Station JAVA 贪心 Medium ♥
135 Candy JAVA 贪心 Hard ♥♥
136 Single Number JAVA 位运算
哈希		 Easy ♥
137 Single Number II JAVA 位运算 Medium ♥
139 Word Break JAVA 动态规划 Medium ♥
140 Word BreakII JAVA 记忆回溯 Hard ♥♥
141 Linked List Cycle JAVA 快慢指针 Easy ♥
142 Linked List Cycle II JAVA 哈希 Medium ♥
143 Reorder List JAVA 链表 Medium ♥♥
144 Binary Tree Preorder Traversal JAVA 二叉树
前序遍历		 Medium ♥♥
145 Binary Tree Postorder Traversal JAVA 二叉树
后序遍历		 Hard ♥♥♥
146 LRU Cache JAVA 哈希表
双向链表		 Medium ♥♥
148 Sort List JAVA 链表排序 Medium ♥
150 Evaluate Reverse Polish Notation JAVA 栈 Medium ♥
152 Maximum Product Subarray JAVA 动态规划 Medium ♥
155 Min Stack JAVA 栈 Easy ♥
160 Intersection of Two Linked List JAVA 链表 Easy ♥♥
164 Maximum Gap JAVA 桶排序 Hard ♥♥
169 Majority Element JAVA 摩尔投票 Easy ♥
173 Binary Search Tree Iterator JAVA 二叉树 Medium
179 Largest Number JAVA 字符串
排序		 Medium ♥♥
188 Best Time to BAS Stock IV JAVA 动态规划 Hard ♥♥♥
189 Rotate Array JAVA 数组 Medium
190 Reverse Bits JAVA 位运算 Easy ♥
191 Number Of 1 Bits JAVA 位运算 Medium ♥
198 House Robber JAVA 动态规划 Easy ♥
199 Binary Tree Right Side View JAVA 二叉树 Medium ♥
200 Number of Islands JAVA DFS Medium ♥
204 Count Primes JAVA 质数
筛		 Easy ♥
205 Isomorphic Strings JAVA 哈希 Easy
206 Reverse Linked List JAVA 链表 Medium ♥
207 Course Schedule JAVA 拓扑排序 Medium ♥
208 Implement Trie JAVA 前缀树 Medium ♥
210 Course Schedule II JAVA 拓扑排序 Medium ♥
213 House Robber II JAVA 动态规划 Medium ♥♥
215 Kth Largest Element in an Array JAVA 快排 Medium ♥
216 Combination Sum III JAVA 回溯
组合		 Medium ♥
221 Maximal Square JAVA 模拟 Medium ♥
222 Count Complete Tree Nodes JAVA 二叉树 Medium ♥
224 Basic Calculator JAVA 栈 Hard ♥♥
226 Invert Binary Tree JAVA 二叉树 Easy ♥
227 Basic Calculator II JAVA 栈 Medium ♥
230 Kth Smallest Element BST JAVA 二叉树 Medium
232 Implement Queue Using Stacks JAVA 队列
栈		 Easy ♥
234 PalindromeLinkedList JAVA 快慢指针
链表反转		 Easy ♥
235 Lowest Common Ancestor of a BST JAVA 二叉搜索
公公祖先		 Easy ♥
236 Lowest Common Ancestor of a Binary Tree JAVA 二叉树
公共祖先
后序遍历		 Median ♥♥
238 Product Of Array Except Self JAVA 数组 Medium ♥
239 Sliding Window Maximum JAVA 单调栈 Hard ♥
240 Search a 2D Matrix II JAVA 数学 Medium ♥
241 [Different Ways to Add Parentheses](https://leetcode-cn.com/problems/different-ways-to-add-parentheses/ JAVA 分治 Medium ♥
263 Ugly Number JAVA 数学 Easy
264 Ugly Number II JAVA 最小堆
动态规划		 Medium ♥♥
279 Perfect Squares JAVA 动态规划 Medium ♥
283 Move Zeroes JAVA 数组 Easy ♥
287 Find the Duplicate Number JAVA 哈希
快慢指针
二分		 Medium ♥
290 Word Pattern JAVA 哈希 Easy ♥
297 Serialize and Deserialize Binary Tree JAVA 二叉树
序列化
反序列化		 Hard ♥♥
300 Longest Increasing Subsequence JAVA 动态规划
贪心		 Medium ♥♥♥
303 Range Sum Query - Immutable JAVA 数组 Easy
304 Range Sum Query 2D - Immutable JAVA 数组 Medium
306 Additive Number JAVA 循环
递归		 Medium ♥♥
309 Best Time To BAS Stock with Cooldown JAVA Medium ♥♥
310 Minimum Height Tree JAVA 层序遍历
最外层		 Medium ♥
312 Burst Balloons JAVA 动态规划 Hard ♥♥
315 Count of Smaller Numbers JAVA 归并** Hard ♥
321 Create Maximum Number JAVA 单调栈
数组		 Hard ♥♥♥
322 Coin Change JAVA 动态规划 Medium ♥
330 Patching Arrays JAVA 贪心 Hard ♥♥
331 Verify Preorder Serialization JAVA 栈 Medium ♥
337 House Robber III JAVA 动态规划 Medium ♥♥
338 Counting Bits JAVA 动态规划
位运算		 Medium ♥♥
341 Flatten Nested List Iterator JAVA DFS Medium ♥
343 Integer Break JAVA 动态规划 Medium ♥♥
344 Reverse String JAVA 双指针 Medium
347 Top K Frequent Elements JAVA 哈希
堆		 Medium ♥
349 Intersection of Two Arrays JAVA 哈希 Easy ♥
350 Intersection of Two Arrays II JAVA 哈希 Easy ♥
357 Count Numbers with Unique Digits JAVA 回溯 Medium ♥
374 Guess Number Higher Or Lower JAVA 二分查找 Easy
375 Guess Number Higher Or Lower II JAVA 动态规划 Medium ♥
381 Insert Delete GetRandom O(1) JAVA 列表
哈希		 Hard ♥
387 First Unique Char in a String JAVA 哈希 Easy
389 Find the Difference JAVA 哈希 Easy
392 Is Subsequence JAVA Easy
394 Decode String JAVA 栈
字符串		 Medium ♥
399 Evaluate Division JAVA 邻接表
图		 Medium ♥♥
402 Remove K Digits JAVA 单调栈 Medium ♥♥
406 Queue Reconstruction by Height JAVA 双层排序 Medium ♥
416 Partition Equal Subset Sum JAVA 动态规划
 Medium ♥♥
424 Longest Repeating Character Rep JAVA 滑动窗口 Medium ♥♥
435 Non-overlapping Intervals JAVA 贪心 Medium ♥
437 Path Sum III JAVA 前缀和
哈希		 Medium ♥♥
438 Find All Anagrams In a String JAVA 滑动窗口
哈希		 Medium ♥
448 Find All Numbers Disappeared JAVA 哈希 Easy ♥
455 Assign Cookies JAVA 贪心 Easy
456 132 Pattern JAVA 单调栈 Medium ♥♥
461 Hamming Distance JAVA 位运算 Easy
463 Island Perimeter JAVA DFS Easy ♥
464 Can I Win JAVA 博弈DP
记忆回溯		 Medium ♥♥
470 Implement Rand10() JAVA 拒绝采样 Medium ♥
474 Ones and Zeroes JAVA 动态规划 Medium ♥♥
475 Heaters JAVA 二分查找
最大最小值		 Easy ♥
485 Max Consecutive Ones JAVA 数组 Easy
494 Target Sum JAVA 枚举
动态规划		 Medium ♥♥
508 Most Frequent Subtree Sum JAVA 后序遍历
哈希		 Medium
509 Fibonacci Number JAVA 动态规划 Easy
516 Longest Palindromic Subsequence JAVA 动态规划 Medium ♥
518 Coin Change II JAVA 动态规划 Medium ♥
520 Detect Capital JAVA Easy
523 Continuous Subarray Sum JAVA 哈希 Medium ♥♥
538 Convert BST to Greater Tree JAVA Easy
543 Diameter of Binary Tree JAVA 后序遍历 Medium ♥
547 Number of Provinces JAVA 连通分量 Medium
554 Brick Wall JAVA 哈希 Medium ♥
560 Subarray Sum Equals K JAVA 哈希
前缀和		 Medium ♥
575 Distribute Candies JAVA 哈希 Easy
581 Shortest Unsorted Continuous Subarray JAVA 双指针 Medium ♥♥
605 Can Place Flowers JAVA 贪心 Easy ♥
617 Merge Two Binary Trees JAVA DFS Easy ♥
621 Task Scheduler JAVA 数学 Medium ♥♥
628 Maximum Product of Three Numbers JAVA 数组 Easy ♥♥
643 Maximum Average Subarray I JAVA 滑动窗口 Easy
647 Palindromic Substring JAVA 中心扩散 Medium ♥
649 Dota2 Senate JAVA 模拟 Medium
650 2 Keys Keyboard JAVA 数学 Medium ♥
665 Non-decreasing Array JAVA 数学 Easy ♥
674 Longest Continuous IS JAVA 数组 Easy
684 Redundant Connection JAVA 判断图环
并查集		 Medium ♥
690 Employee Importance JAVA 哈希
DFS		 Easy ♥
692 Top K Frequent Words JAVA 哈希
最小堆		 Medium ♥♥
705 Design HashSet JAVA 哈希 Easy
706 Design HashMap JAVA 哈希 Medium ♥
714 Best Time to Buy and Sell Stock WTF JAVA 动态规划 Medium ♥
721 Accounts Merge JAVA 并查集 Medium ♥
724 Find Pivot Index JAVA 数组 Easy
738 Monotone Increasing Digits JAVA 贪心
字符串		 Medium ♥♥
739 Daily Temperatures JAVA 单调栈 Medium ♥
740 Delete and Earn JAVA 动态规划 Medium ♥♥
746 Min Cost Climbing Stairs JAVA 动态规划 Easy ♥
767 Reorganize String JAVA 贪心 Medium ♥
771 Jewels and Stones JAVA 哈希 Easy
781 Rabbits in Forest JAVA 数学 Medium ♥
783 Minimum Distance Between BST Nodes JAVA 二叉搜索 Easy
787 Cheapest Flights Within K Stops 动态规划 Medium ♥♥
784 Letter Case Permutation JAVA 全排列 Easy ♥
815 Bus Routes JAVA BFS Hard ♥
830 Positions of Large Groups JAVA 数组 Easy
832 Flipping an image JAVA 模拟 Easy
837 New 21 Game JAVA 动态规划 Medium ♥♥
839 Similar String Groups JAVA 并查集 Hard ♥
842 Split Array into Fibonacci Sequence JAVA 回溯 Medium ♥♥
844 Backspace String Compare JAVA 栈 Easy
860 Lemonade Change JAVA 模拟 Easy
861 Score After Flipping Matrix JAVA 贪心 Medium ♥
867 Transpose Matrix JAVA 数组 Easy
872 Leaf-Similar Trees JAVA DFS Easy
877 Stone Game JAVA 博弈DP Medium ♥♥
887 Super Egg Drop JAVA 动态规划
二分查找		 Hard ♥♥♥
888 Fair Candy Swap JAVA 数学
哈希		 Easy ♥
896 Monotonic Array JAVA 数组 Easy
912 Sort an Array JAVA 快速排序 Median ♥
938 Range Sum of BST JAVA 平衡二叉 Easy
941 Valid Mountain Array JAVA 数组 Easy ♥
947 Most Stones Removed with SRC JAVA 并查集 Medium ♥
973 K Closest Points to Origin JAVA 快排 Medium ♥
976 Largest Perimeter Triangle JAVA 贪心 Easy ♥
977 Squares of a Sorted Array JAVA 双指针 Easy ♥
978 Longest Turbulent Subarray JAVA 动态规划 Medium ♥
989 Add to Array-Form of Integer JAVA 数组 Easy
992 Subarrays with K Different I JAVA 滑动窗口 Hard ♥♥
993 Cousins in Binary Tree JAVA BFS Easy ♥
1002 Find Common Characters JAVA
1006 Clumsy Factorial JAVA 栈 Medium ♥
1011 Capacity To Ship Packages JAVA 二分查找 Medium ♥♥
1018 Binary Prefix Divisible by 5 JAVA 进制 Easy ♥
1030 Matrix Cells in Distance Order JAVA 模拟 Easy
1035 Uncrossed Lines JAVA 动态规划 Medium ♥
1038 BST to Greater Sum Tree JAVA 二叉树
中序遍历		 Median ♥
1046 Last Stone Weight JAVA 堆 Easy ♥
1047 Remove All Adjacent Duplicates JAVA 栈 Easy ♥
1052 Grumpy Bookstore Owner JAVA 滑动窗口 Medium ♥
1105 Filling Bookcase Shelves JAVA 动态规划 Medium ♥♥
1114 Print In Order JAVA 并发 Easy ♥
1115 Print FooBar Alternately JAVA 并发 Medium ♥
1116 Print Zero Even Odd JAVA 并发 Medium ♥
1117 Building H2O JAVA 并发 Medium ♥
1128 Number of Equivalent Domino JAVA 哈希 Easy ♥
1143 Longest Common Subsequence JAVA 动态规划 Medium
1079 Letter Tile Possibilities JAVA 回溯
剪枝		 Medium ♥
1202 Smallest String with Swaps JAVA 并查集 Medium ♥♥
1203 Sort Items by Group JAVA 双层拓扑 Hard ♥♥
1207 Unique Number of Occurrences JAVA 哈希 Easy
1208 Get Equal Substrings Within Budget JAVA 滑动窗口 Medium ♥
1219 Path With Maximum Gold JAVA DFS
回溯		 Medium ♥
1232 Check if it is a straight line JAVA 数学 Easy
1295 Find Numbers with Even Number of Digits JAVA Easy
1310 XOR Queries of a Subarray JAVA 前缀异或 Medium ♥
1314 Unique Substrings in Wraparound String JAVA 动态规划
字典		 Medium ♥♥
1356 Sort Integers by The Number of 1 Bits JAVA 数组
排序
位运算		 Easy ♥
1367 Linked List in Binary Tree JAVA 二叉树
遍历		 Median ♥
1411 Number of Ways to Patin 3N Grid JAVA 数学
动态规划		 Hard ♥
1415 The k-th Lexicographical String JAVA 回溯 Median ♥
1423 Maximum Points You Can Obtain JAVA 滑动窗口 Medium ♥
1482 Minimum Number of Days to MmB JAVA 二分法 Medium ♥
1486 XOR Operation in An Array JAVA 位运算 Easy
1539 Kth Missing Positive Number JAVA 数组 Easy ♥
1584 Min Cost to Connect All Points JAVA 生成树 Medium ♥♥
1631 Path With Minimum Effort JAVA 最短路径 Medium ♥
1720 Decode XORed Array JAVA 位运算 Easy
1723 Find Minimum Time to Finish All jobs JAVA 回溯
剪枝		 Hard ♥♥
1734 Decode XORed Permutation JAVA 异或 Medium ♥

LCCI

# Title Solution Tag Difficulty Significance
04.10 Check SubTree LCCI JAVA 二叉树 Median ♥
08.11 Coin LCCI JAVA 动态规划
完全背包		 Medium ♥♥

LCOF

# Title Solution Tag Difficulty Significance
03 数组中重复的数字 JAVA 哈希 Easy
04 二维数组中的查找 JAVA 二维数组 Medium ♥
05 替换空格 JAVA 字符串 Easy
06 从尾到头打印链表 JAVA 链表 Easy
07 重建二叉树 JAVA 递归 Medium ♥
09 用两个栈实现队列 JAVA 栈 Easy
10 斐波拉契数列 JAVA 动态规划 Easy
11 旋转数组的最小数组 JAVA 二分 Hard ♥♥
12 矩阵中的路径 JAVA 回溯 Medium ♥
13 机器人的运动范围 JAVA DFS Medium ♥
14 剪绳子-I JAVA 动态规划 Medium ♥
15 二进制中1的个数 JAVA 位运算 Easy
16 数值的整数次方 JAVA 快速幂 Medium ♥
17 打印从1到最大的n位数 JAVA 全排列 Easy ♥
18 删除链表的节点 JAVA 链表 Easy ♥
19 正则表达式匹配 JAVA 动态规划 Hard ♥
20 表示数值的字符串 JAVA 边界条件 Medium ♥
21 调整数组顺序使奇数位于偶数前面 JAVA 快排** Easy ♥♥
22 链表中倒数第k个节点 JAVA 链表 Easy
24 反转链表 JAVA 链表 Easy
25 合并两个排序的链表 JAVA 链表 Easy
26 树的子结构 JAVA 树遍历 Medium
27 二叉树的镜像 JAVA 递归 Easy
28 对称的二叉树 JAVA 递归 Easy
29 顺时针打印矩阵 JAVA 模拟 Easy
30 包含min函数的栈 JAVA 辅助栈 Easy ♥
31 栈的入、弹出序列 JAVA 模拟 Medium ♥♥
32 从上到下打印二叉树 JAVA 层序遍历 Medium
33 二叉搜索树的后序遍历序列 JAVA 递归 Medium ♥&herats;
34 二叉树中和为某一值的路径 JAVA 回溯
DFS		 Medium ♥
35 复杂链表的复制 JAVA 哈希 Medium ♥
36 二叉搜索树与双向链表 JAVA 中序遍历
链表		 Medium ♥♥
37 序列化二叉树 JAVA 层序遍历
序列化		 Hard ♥
38 字符串的排列 JAVA 回溯
排列		 Medium ♥♥
39 数组中出现次数超过一半的数字 JAVA 摩尔投票 Easy ♥♥
40 最小的k个数 JAVA 快排
堆		 Easy ♥♥
41 数据流中的中位数 JAVA 对顶堆 Hard ♥♥
42 连续子数组的最大和 JAVA 动态规划 Easy ♥
43 1~n整数中1出现的次数 JAVA 数学
找规律		 Hard ♥♥
44 数字序列中某一位的数字 JAVA 数学
找规律		 Medium ♥♥
45 把数组排成最小的数 JAVA 数学
特殊排序		 Medium ♥♥
46 把数字翻译成字符串 JAVA 动态规划 Medium ♥
47 礼物的最大价值 JAVA 动态规划 Medium
48 最长不含重复字符的子字符串 JAVA 滑动窗口 Medium ♥♥
49 丑数 JAVA 动态规划 Medium ♥♥
50 第一个只出现一次的字符 JAVA 哈希 Easy
51 数组中的逆序对 JAVA 逆序对
归并排序		 Hard ♥♥
52 两个链表中的第一个公共节点 JAVA 双指针 Easy ♥
53 在排序数组中查找数字 JAVA 二分法 Easy ♥♥
53 0~n-1中缺失的数字 JAVA 二分 Easy ♥
54 二叉搜索树的第k大节点 JAVA 反中序遍历 Easy ♥
55 二叉树的深度 JAVA 递归 Easy
56 数组中数字出现的次数 JAVA 异或 Medium ♥♥
56 数组中数字出现的次数II JAVA 位操作 Medium ♥♥
57 和为s的两个数字 JAVA 双指针 Easy ♥
57 和为s的连续正数序列 JAVA 滑动窗口 Easy
58 翻转单词顺序 JAVA 字符串 Easy
58 左旋转字符串 JAVA 字符串 Easy
59 滑动窗口的最大值 JAVA 堆
单调队列		 Hard ♥
59 队列的最大值 JAVA 单调队列 Medium ♥♥
60 n个骰子的点数 JAVA 动态规划 Medium ♥♥
61 扑克牌中的顺子 JAVA 模拟 Easy
62 圆圈中最后剩下的数字 JAVA 约瑟夫环
动态规划		 Easy ♥♥
63 股票的最大利润 JAVA 最小值 Medium
64 求1+2+..+n [JAVA](./src/lcof/Offer64.java 短路效应 Medium
65 不用加减乘除做加法 JAVA 位运算 Easy
66 构建乘积数组 JAVA 动态规划 Medium ♥♥
67 把字符串转换成整数 JAVA 字符串 Medium ♥

周赛

# Title Solution Tag Difficulty Significance
5416 Check Word Prefix JAVA Easy
5417 Maximum Number of Vowels JAVA 滑动窗口 Median ♥
5418 Pseudo-Palindromic Paths Binary Tree JAVA 回文序列
二叉树		 Median ♥
5419 Max Dot Product of Two Subsequences JAVA 动态规划 Hard ♥
5519 Rearrange Spaces Between Words JAVA 字符串 Easy ♥
5520 Split a String into the Max Number JAVA 回溯 Medium ♥
5521 Maximum Non Negative Product in a Matrix JAVA 动态规划 Medium ♥