leetcode 题解，记录自己的 leetcode 解题之路。
不会算法的程序员，是没有灵魂的！
对于算法类的题目主要的分类，借用一张leetcode的图片：
其中算法，主要是以下几种：
- 基础技巧：分治、二分、贪心
- 排序算法：快速排序、归并排序、计数排序
- 搜索算法：回溯、递归、深度优先遍历，广度优先遍历，二叉搜索树等
- 图论：最短路径、最小生成树
- 动态规划：背包问题、最长子序列
数据结构，主要有如下几种：
- 数组与链表：单 / 双向链表
- 栈与队列
- 哈希表
- 堆：最大堆 ／ 最小堆
- 树与图：最近公共祖先、并查集
- 字符串：前缀树（字典树） ／ 后缀树
这里仅列举具有代表性题目，并不是全部题目
- 0020.Valid Parentheses
- 0026.remove-duplicates-from-sorted-array
- 0053.maximum-sum-subarray
- 0088.merge-sorted-array
- 0104.maximum-depth-of-binary-tree
- 0121.best-time-to-buy-and-sell-stock
- 0122.best-time-to-buy-and-sell-stock-ii
- 0125.valid-palindrome
- 0136.single-number
- 0155.min-stack
- 0167.two-sum-ii-input-array-is-sorted
- 0169.majority-element
- 0172.factorial-trailing-zeroes
- 0190.reverse-bits
- 0191.number-of-1-bits
- 0198.house-robber
- 0203.remove-linked-list-elements
- 0206.reverse-linked-list
- 0219.contains-duplicate-ii
- 0226.invert-binary-tree
- 0232.implement-queue-using-stacks
- 0263.ugly-number
- 0283.move-zeroes
- 0342.power-of-four
- 0349.intersection-of-two-arrays
- 0437.path-sum-iii
- 0371.sum-of-two-integers
- 0501.find-mode-in-binary-search-tree
- 0575.distribute-candies
- 0874.walking-robot-simulation
- 1260.shift-2d-grid
- 1332.remove-palindromic-subsequences
- 0002. Add Two Numbers
- 0003. Longest Substring Without Repeating Characters
- 0005.longest-palindromic-substring
- 0011.container-with-most-water
- 0015.3-sum
- 0019. Remove Nth Node From End of List
- 0024. Swap Nodes In Pairs
- 0029.divide-two-integers
- 0031.next-permutation
- 0033.search-in-rotated-sorted-array
- 0039.combination-sum
- 0040.combination-sum-ii
- 0046.permutations
- 0047.permutations-ii
- 0048.rotate-image
- 0049.group-anagrams
- 0050.pow-x-n
- 0055.jump-game
- 0056.merge-intervals
- 0060.permutation-sequence
- 0062.unique-paths
- 0073.set-matrix-zeroes
- 0075.sort-colors
- 0078.subsets
- 0079.word-search
- 0080.remove-duplicates-from-sorted-array-ii
- 0086.partition-list
- 0090.subsets-ii
- 0091.decode-ways
- 0092.reverse-linked-list-ii
- 0094.binary-tree-inorder-traversal
- 0095.unique-binary-search-trees-ii
- 0096.unique-binary-search-trees
- 0098.validate-binary-search-tree
- 0102.binary-tree-level-order-traversal
- 0103.binary-tree-zigzag-level-order-traversal
- 0113.path-sum-ii
- 0129.sum-root-to-leaf-numbers
- 0130.surrounded-regions
- 0131.palindrome-partitioning
- 0139.word-break
- 0144.binary-tree-preorder-traversal
- 0150.evaluate-reverse-polish-notation
- 0152.maximum-product-subarray
- 0199.binary-tree-right-side-view
- 0200.number-of-islands
- 0201.bitwise-and-of-numbers-range
- 0208.implement-trie-prefix-tree
- 0209.minimum-size-subarray-sum
- 0211.add-and-search-word-data-structure-design
- 0215.kth-largest-element-in-an-array
- 0221.maximal-square
- 0229.majority-element-ii
- 0230.kth-smallest-element-in-a-bst
- 0236.lowest-common-ancestor-of-a-binary-tree
- 0238.product-of-array-except-self
- 0240.search-a-2-d-matrix-ii
- 0279.perfect-squares
- 0309.best-time-to-buy-and-sell-stock-with-cooldown
- 0322.coin-change
- 0328.odd-even-linked-list
- 0334.increasing-triplet-subsequence
- 0365.water-and-jug-problem
- 0378.kth-smallest-element-in-a-sorted-matrix
- 0380.insert-delete-getrandom-o1
- 0416.partition-equal-subset-sum
- 0445.add-two-numbers-ii
- 0454.4-sum-ii
- 0474.ones-and-zeros
- 0494.target-sum
- 0516.longest-palindromic-subsequence
- 0518.coin-change-2
- 0547.friend-circles
- 0609.find-duplicate-file-in-system
- 0875.koko-eating-bananas
- 0877.stone-game
- 0887.super-egg-drop
- 0900.rle-iterator
- 0912.sort-an-array
- 0935.knight-dialer
- 1011.capacity-to-ship-packages-within-d-days
- 1014.best-sightseeing-pair
- 1015.smallest-integer-divisible-by-k
- 1019.next-greater-node-in-linked-list
- 1020.number-of-enclaves
- 1023.camelcase-matching
- 1031.maximum-sum-of-two-non-overlapping-subarrays
- 1104.path-in-zigzag-labelled-binary-tree
- 1131.maximum-of-absolute-value-expression
- 1186.maximum-subarray-sum-with-one-deletion
- 1218.longest-arithmetic-subsequence-of-given-difference
- 1227.airplane-seat-assignment-probability
- 1261.find-elements-in-a-contaminated-binary-tree
- 1262.greatest-sum-divisible-by-three
- 1297.maximum-number-of-occurrences-of-a-substring
- 1310.xor-queries-of-a-subarray
- 1334.find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance
- 0004.median-of-two-sorted-array
- 0023.merge-k-sorted-lists
- 0025.reverse-nodes-in-k-group
- 0030.substring-with-concatenation-of-all-words
- 0032.longest-valid-parentheses
- 0042.trapping-rain-water
- 0084.largest-rectangle-in-histogram
- 0085.maximal-rectangle
- 0124.binary-tree-maximum-path-sum
- 0128.longest-consecutive-sequence
- 0145.binary-tree-postorder-traversal
- 0212.word-search-ii
- 0239.sliding-window-maximum
- 0295.find-median-from-data-stream
- 0301.remove-invalid-parentheses
- 0335.self-crossPing
- 0460.lfu-cache
- 0472.concatenated-words
- 0493.reverse-pairs
- 1168.optimize-water-distribution-in-a-village
接下来打算按tag进行做题