leetcode

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Algorithms

• 1 Two Sum
• 2 Add Two Numbers
• 3 Longest Substring Without Repeating Characters(DP)
• 4 Median of Two Sorted Arrays(二分查找，有序数组求第k大的数)
• 7 Reverse Integer(溢出检测)
• 8 String to Integer (atoi)(溢出检测)
• 9 Palindrome Number
• 10 Regular Expression Matching(递归)
• 11 Container With Most Water
• 12 Integer to Roman(整数转罗马数，静态表)
• 13 Roman to Integer(罗马转整数，静态表)
• 14 Longest Common Prefix
• 15 3Sum
• 17 Letter Combinations of a Phone Number
• 18 4Sum
• 19 Remove Nth Node From End of List(先后指针)
• 20 Valid Parentheses(栈)
• 21 Merge Two Sorted Lists(归并)
• 22 Generate Parentheses(递归、搜索)
• 23 Merge k Sorted Lists(堆)
• 24 Swap Nodes in Pairs(链表操作)
• 25 Reverse Nodes in k-Group(链表操作)
• 26 Remove Duplicates from Sorted Array
• 27 Remove Element
• 28 Implement strStr()(KMP)
• 29 Divide Two Integers(位运算、最小负数绝对值、溢出检测)
• 31 Next Permutation(全排列)
• 33 Search in Rotated Sorted Array(二分搜索)
• 34 Search for a Range(二分)
• 35 Search Insert Position(二分查找)
• 36 Valid Sudoku(数独、hash表)
• 38 Count and Say(字符串和数字转化详解)
• 43 Multiply Strings(大数乘法)
• 46 Permutations(全排列)
• 47 Permutations II(全排列)
• 49 Anagrams(字符串，回文构词)
• 50 Pow(x, n)(二分，浮点数比较，INT_MIN绝对值)
• 53 Maximum Subarray(DP, 最大连续之和)
• 58 Length of Last Word
• 60 Permutation Sequence(康托展开)
• 64 Minimum Path Sum(DP,空间压缩)
• 65 Valid Number(细节题,状态机)
• 66 Plus One
• 67 Add Binary
• 69 Sqrt(x)(二分法，位运算)
• 72 Edit Distance(DP)
• 74 Search a 2D Matrix(二分搜索扩展(二维))
• 75 Sort Colors(O(1)空间，O(n)排序)
• 78 Subsets(递归、回溯、DFS)
• 79 Word Search(DFS、回溯)
• 82 Remove Duplicates from Sorted List II(链表操作
• 83 Remove Duplicates from Sorted List(链表操作)
• 86 Partition List(链表操作，类似于插入排序)
• 88 Merge Sorted Array(归并数组)
• 89 Gray Code(格雷码)
• 90 Subsets II(迭代)
• 92 Reverse Linked List II(链表逆转)
• 94 Binary Tree Inorder Traversal(中序遍历，迭代法)
• [96 Unique Binary Search Trees(迭代)](algorithms/Unique Binary Search Trees)
• 97 Interleaving String(DP)
• 98 Validate Binary Search Tree(BST, 中序遍历)
• 100 Same Tree(相同树，遍历)
• 101 Symmetric Tree(对称树)
• 102 Binary Tree Level Order Traversal(层次遍历)
• 104 Maximum Depth of Binary Tree(树深度)
• 107 Binary Tree Level Order Traversal II(层次遍历)
• 110 Balanced Binary Tree(平衡树)
• 111 Minimum Depth of Binary Tree
• 112 Path Sum(前序遍历)
• 113 Path Sum II(前序遍历)
• 114 Flatten Binary Tree to Linked List(后序遍历)
• 116 Populating Next Right Pointers in Each Node(层次遍历)
• 117 Populating Next Right Pointers in Each Node II(层次遍历，O(1)空间，指针操作
• 118 Pascal's Triangle(杨辉三角)
• 119 Pascal's Triangle II(杨辉三角第k行，求最大公约数
• 120 Triangle(DP,空间压缩)
• 121 Best Time to Buy and Sell Stock(最大数对之差，DP
• 122 Best Time to Buy and Sell Stock II(贪心算法)
• 123 Best Time to Buy and Sell Stock III(动态规划)
• 125 Valid Palindrome
• 128 Longest Consecutive Sequence
• 129 Sum Root to Leaf Numbers(前序遍历)
• 136 Single Number(位运算)
• 138 Copy List with Random Pointer(链表扩展，随机链表拷贝)
• 139 Word Break(DP,记忆搜索)
• 141 Linked List Cycle(快慢指针法)
• 142 Linked List Cycle II
• 143 Reorder List(链表操作，指针中间节点，逆转链表)
• 144 Binary Tree Preorder Traversal(迭代法前序遍历
• 145 Binary Tree Postorder Traversal(后序遍历)
• 146 LRU Cache(空间换时间)
• 147 Insertion Sort List(链表操作，插入排序)
• 148 Sort List(归并排序)
• 150 Evaluate Reverse Polish Notation(栈的应用)
• 151 Reverse Words in a String
• 152 Maximum Product Subarray(DP,最大连续之积)
• 153 Find Minimum in Rotated Sorted Array(二分)
• 154 Find Minimum in Rotated Sorted Array II(二分)
• 155 Min Stack(数据结构设计、栈的使用)
• 160 Intersection of Two Linked Lists
• 162 Find Peak Element(二分)
• 165 Compare Version Numbers
• 168 Excel Sheet Column Title(进制转化)
• 169 Majority Element
• 171 Excel Sheet Column Number(进制转化)
• 172 Factorial Trailing Zeroes
• 179 Largest Number(排序)
• 189 Rotate Array
• 190 Reverse Bits
• 191 Number of 1 Bits(位运算)
• 198 House Robber(DP)
• 199 Binary Tree Right Side View(层次遍历)
• 200 Number of Islands(递归标记、搜索)
• 201 Bitwise AND of Numbers Range(位运算)
• 202 Happy Number(环判断，模拟)
• 203 Remove Linked List Elements(链表操作)
• 204 Count Primes(素数,埃拉托斯特尼筛法)
• 205 Isomorphic Strings
• 206 Reverse Linked List(链表转置，递归&迭代)
• 207 Course Schedule(拓扑排序、图是否存在环、BFS、DFS)
• 208 Implement Trie (Trie树、字典树、前缀树)
• 210 Course Schedule II(拓扑排序)
• 211 Add and Search Word - Data structure design(Trie树)
• 213 House Robber II(DP)
• 215 Kth Largest Element in an Array(快排partition函数)
• 217 Contains Duplicate(hashset)
• 219 Contains Duplicate II(hashmap)
• 226 Invert Binary Tree(递归，树)
• 228 Summary Ranges
• 230 Kth Smallest Element in a BST(BST、中序遍历)
• 231 Power of Two(位运算，二进制1的个数)
• 232 Implement Queue using Stacks(栈模拟队列)
• 234 Palindrome Linked List(链表逆转、回文链表)
• 235 Lowest Common Ancestor of a Binary Search Tree(LCA, 最低公共祖先,二叉搜索树)
• 236 Lowest Common Ancestor of a Binary Tree(LCA,最低公共祖先，二叉树
• 237 Delete Node in a Linked List(O(1)删除单链表节点)
• 238 Product of Array Except Self(数组操作)
• 242 Valid Anagram(hash表，判断两个字符串出现的字符和次数均相同)
• 337 House Robber III(DFS，递归)
• 338 Counting Bits(二进制1的个数，迭代法)

Database

• 175 Combine Two Tables (表连接详解)
• 176 Second Highest Salary (子查询)
• 177 Nth Highest Salary(定义函数，变量，分支结构)
• 178 Rank Scores (导出表、聚集)
• 180 Consecutive Numbers(case语句)
• 181 Employees Earning More Than Their Managers(自连接)
• 182 Duplicate Emails(分组过滤)
• 183 Customers Who Never Order(exists子句)
• 184 Department Highest Salary(聚集分组详解)
• 196 Delete Duplicate Emails(连接删除)
• 197 Rising Temperature(自连接，日期比较)

Shell

• 192 Word Frequency (关联数组)
• 193 Valid Phone Numbers (grep)
• 194 Transpose File (awk)
• 195 Tenth Line (sed)