https://leetcode.com/problemset/all/

1. 知识储备

1.1. 语言选择

⭐️C++：向下兼容C语言，拥有多个封装好的函数
Java

1.2. 算法思想

双指针

排序

贪心思想

二分查找

分治

搜索（DFS，BFS）

动态规划

数学知识

1.3. 数据结构

官网总结

2. 如何刷题

按类型tag刷题，每个类型10-20题(动态规划：多多益善)

周一：树/链表 (树最容易培养框架思维-递归/DFS/BFS)

周二：搜索

周三：动态规划 …

第一遍：5分钟想不出来就看答案

第二遍：尝试不看答案完整实现，不超过60分钟

第三遍：快速实现

看别人的代码(论坛)，至少3-5种不同的实现，分析优缺点，速度快慢

学习新的语言，算法，数据结构，API，模版

完整的手写实现，不要copy代码，增强肌肉记忆

运行时间70%左右的代码，阅读提高能力

扩宽思路-使用什么算法，推算时间复杂度，统一代码风格，取有意义的变量名

《剑指offer》覆盖基本题型
Top 100 Liked 高频题，Top 100 interview 经典题
重复刷2-3遍，看到题就有思路
按照公司tag刷，facebook，google，amazon - 一亩三分地
公司面经

3. 网站推荐

Up主：土妹编程花花酱的表世界

CSNotes：https://github.com/CyC2018/CS-Notes

牛客网：https://www.nowcoder.com/ta/job-code-high-week

codetop：https://codetop.cc/home

leetcode：

官网 https://leetcode.com/problemset/all/

中文 https://leetcode-cn.com/problemset/all/

4. 挑战赛

leetcode周赛 https://leetcode.com/contest/

牛客月赛

codetop按公司及岗位

5. 解析思路

https://zxi.mytechroad.com/blog/leetcode-problem-categories/

5.1. Tree（树）

Id	Name	Difficulty	Similar Problems	Comments
94	Binary Tree Inorder Traversal	★	144 145 429 589 590	traversal
100	Same Tree	★★	101 110 111 572 965
102	Binary Tree Level Order Traversal	★★	107 429 872	collecting nodes
814	Binary Tree Pruning	★★★	669 1325
112	Path Sum	★★★	113 437
129	Sum Root to Leaf Numbers	★★★	257
236	Lowest Common Ancestor of a Binary Tree	★★★	235
297	Serialize and Deserialize Binary Tree	★★★	449
508	Most Frequent Subtree Sum	★★★
124	Binary Tree Maximum Path Sum	★★★	543 687	Use both children, return one
968	Binary Tree Cameras	★★★★	337 979

5.2. Divide and conquer（分治）

Id	Name	Difficulty	Similar Problems	Comments
169	Majority Element	★★		你知道茴香豆的茴有几种写法吗？
153	Find Minimum in Rotated Sorted Array	★★	154
912	Sort and Array	★★★		merge sort
315	Count of Smaller Numbers After Self	★★★★		merge sort / BIT

5.3. List（链表）

Id	Name	Difficulty	Similar Problems	Comments
2	Add Two Numbers	★★	445	traversal
24	Swap Nodes in Pairs	★★		reverse
206	Reverse Linked List	★★		reverse
141	Linked List Cycle	★★	142	priority_queue / mergesort
23	Merge k Sorted Lists	★★★	21	priority_queue / mergesort
147	Insertion Sort List	★★★		insertion sort
148	Sort List	★★★★		merge sort O(1) space
707	Design Linked List	★★★★

5.4. BST（二叉搜索树）

Id	Name	Difficulty	Similar Problems	Comments
98	Validate Binary Search Tree	★★	530	inorder
700	Search in a Binary Search Tree	★★	701	binary search
230	Kth Smallest Element in a BST	★★★		inorder
99	Recover Binary Search Tree	★★★		inorder
108	Convert Sorted Array to Binary Search Tree	★★★		build BST
501	Find Mode in Binary Search Tree	★★★		inorder
450	Delete Node in a BST	★★★★		binary search

5.5. Graph（图论）

Id	Name	Difficulty	Similar Problems	Comments
133	Clone Graph	★★	138
200	Number of Islands	★★	547 695 733 827 1162	grid + connected components
841	Keys and Rooms	★★	1202
207	Course Schedule	★★★	210 802
399	Evaluate Division	★★★	839 952 990 721 737	union find
785	Is Graph Bipartite?	★★★	886 1042	bipartition, graph coloring
997	Find the Town Judge	★★★		in/out degrees
433	Minimum Genetic Mutation	★★★	815 863 1129 1263	unweighted shortest path / BFS
684	Redundant Connection	★★★★	685 1319	cycle, union find
743	Network Delay Time	★★★★	787 882 924 1334	weighted shortest path
847	Shortest Path Visiting All Nodes	★★★★	864 1298	BFS
332	Reconstruct Itinerary	★★★★		Eulerian path
1192	Critical Connections in a Network	★★★★		Tarjan
943	Find the Shortest Superstring	★★★★★	980 996	Hamiltonian path (DFS / DP)
959	Regions Cut By Slashes	★★★★★		union find / grid + CCs

5.6. Search (BFS/DFS)（搜索/回溯）

Id	Name	Difficulty	Similar Problems	Comments
17	Letter Combinations of a Phone Number	★★	39 40 77 78 90 216	Combination
46	Permutations	★★	47 784 943 996	Permutation
22	Generate Parentheses	★★★	301	DFS
37	Sudoku Solver	★★★	51 52	DFS
79	Word Search	★★★	212	DFS
127	Word Ladder	★★★★	126 752 818	BFS
542	01 Matrix	★★★	675 934	BFS
698	Partition to K Equal Sum Subsets	★★★	93 131 241 282 842	Partition

5.7. Binary Search（二分搜索）

Id	Name	Difficulty	Similar Problems	Comments
35	Search Insert Position	★★	34 704 981	upper_bound
33	Search in Rotated Sorted Array	★★★	81 153 154 162 852	rotated / peak
69	Sqrt(x)	★★★		upper_bound
74	Search a 2D Matrix	★★★		treat 2d as 1d
875	Koko Eating Bananas	★★★	1011	guess ans and check
4	Median of Two Sorted Arrays	★★★★
378	Kth Smallest Element in a Sorted Matrix	★★★★	668	kth + matrix
719	Find K-th Smallest Pair Distance	★★★★	786	kth + two pointers

5.8. Two Pointers（双指针）

Id	Name	Difficulty	Similar Problems	Comments
11	Container With Most Water	★★	42
125	Valid Palindrome	★★	455
917	Reverse Only Letters	★★	925 986 855
167	Two Sum II – Input array is sorted	★★★	15 16
977	Squares of a Sorted Array	★★		merge sort
992	Subarrays with K Different Integers	★★★★

5.9. Advanced（高级）

Id	Name	Difficulty	Similar Problems	Comments
208	Implement Trie (Prefix Tree)	★★★	648 676 677 720 745 211	Trie
307	Range Sum Query – Mutable	★★★		BIT/Segment Tree
901	Online Stock Span	★★★	907 1019	monotonic stack
239	Sliding Window Maximum	★★★		monotonic queue

5.10. DP（动态规划）

Id	Name	Difficulty	Similar Problems	Comments
70	Climbing Stairs	★	746 1137	I: O(n), S = O(n), T = O(n)
303	Range Sum Query – Immutable	★	1218	I: O(n), S = O(n), T = O(n)
53	Maximum Subarray	★★	121	I: O(n), S = O(n), T = O(n)
62	Unique Paths	★★	63 64 120 174 931 1210	I: O(mn), S = O(mn), T = O(mn)
85	Maximal Rectangle	★★★	221 304 1277	I: O(mn), S = O(mn), T = O(mn)
198	House Robber	★★★	213 309 740 790 801	I: O(n), S = O(3n), T = O(3n)
279	Perfect Squares	★★★		I: n, S = O(n), T = O(n*sqrt(n))
139	Word Break	★★★	140 818	I: O(n), S = O(n), T = O($n^2$)
300	Longest Increasing Subsequence	★★★	673 1048	I: O(n), S = O(n), T = O($n^2$)
96	Unique Binary Search Trees	★★★		I: O(n), S = O(n), T = O($n^2$)
1105	Filling Bookcase Shelves	★★★		I: O(n) + t, S = O(n), T = O($n^2$)
131	Palindrome Partitioning	★★★	89	I: O(n), S = O(2^n), T = O($2^n$)
72	Edit Distance	★★★	10 44 97 115 583 1187 1143 1092 718 712	I: O(m+n), S = O(mn), T = O(mn)
1139	Largest 1-Bordered Square	★★★		I: O(mn), S = O(mn) T = O(mn*min(n,m))
688	Knight Probability in Chessboard	★★★	576 935	I: O(mn) + k S = O(kmn), T = O(kmn)
322	Coin Change	★★★	377 416 494 1043 1049 1220 1230 1262 1269	I: O(n) + k, S = O(n), T = O(kn)
813	Largest Sum of Averages	★★★★	1278 1335 410	I: O(n) + k，S = O(nk), T = O(k$n^2$)
1223	Dice Roll Simulation	★★★★		I: O(n) + k + p，S = O(kp), T = O($n^2$kp)
312	Burst Balloons	★★★★	664 1024 1039 1140 1130	I: O(n), S = O($n^2$), T = O($n^3$)
741	Cherry Pickup	★★★★		I: O($n^2$), S = O($n^3$), T = O($n^3$)
546	Remove Boxes	★★★★★		I: O(n), S = O($n^3$), T = O($n^4$)
943	Find the Shortest Superstring	★★★★★	980 996 1125	I: O(n)，S = O(nx$2^n$), T = ($n^2$*$2^n$)

W.T.的博客

Leetcode刷题