①leetcode 207-226 反转二叉树 https://leetcode-cn.com/problems/invert-binary-tree/solution/ 查找第k个最大元素 https://leetcode-cn.com/problems/kth-largest-element-in-an-array/submissions/ 实现前缀树(在公共空间声明，在构造函数初始化) https://leetcode-cn.com/problems/implement-trie-prefix-tree/solution/qian-zhui-shu-by-19216801-h9e2/ D...

①leetcode 160-206 相交链表的第一个节点 https://leetcode-cn.com/problems/intersection-of-two-linked-lists/submissions/ 数组中超过一半的元素 https://leetcode-cn.com/problems/majority-element/solution/ 打家劫舍（dp） https://leetcode-cn.com/problems/house-robber/ 岛屿数量 https://leetcode-cn.com/problems/number-of-islands/solution/...

①leetcode 至今，按顺序刷到了140题，剩下的10天刷完top100，把时间转移到项目和八股文上。 快慢指针找链表环 https://leetcode-cn.com/problems/linked-list-cycle/submissions/ 找入环节点证明 https://leetcode-cn.com/problems/linked-list-cycle-ii/solution/huan-xing-lian-biao-ii-by-leetcode-solution/ 链表排序 O（n²）解法可以使用插入 本题要求O（NlogN）的解法，快排，归并，和堆是O（NlogN）的，使用快...

①leetcode 复习111-120 数组中出现一次的数字（异或） https://leetcode-cn.com/problems/single-number/submissions/ 找数组中出现三次的数字（32位分别%3，或数电） https://leetcode-cn.com/problems/single-number-ii/submissions/ 复制带random的链表 https://leetcode-cn.com/problems/copy-list-with-random-pointer/submissions/ 单词拆分判断：（dp） https://leetcode...

①leetcode 复习：101-110 回溯+dp 回文子串 https://leetcode-cn.com/problems/palindrome-partitioning/solution/hui-su-dpyou-hua-by-19216801-j46l/ 回文串2（两个dp） https://leetcode-cn.com/problems/palindrome-partitioning-ii/submissions/ 复制图 https://leetcode-cn.com/problems/clone-graph/submissions/ 负数油表 最近发现只要是字符串相关的问题就...

①leetcode 复习91-100 单词接龙2 https://leetcode-cn.com/problems/word-ladder-ii/solution/dan-ci-jie-long-2-by-19216801-rhtn/ 单词接龙 https://leetcode-cn.com/problems/word-ladder/ 最长序列 https://leetcode-cn.com/problems/longest-consecutive-sequence/solution/zui-chang-xu-lie-by-19216801-4wzi/ 根节点到叶节点的数字和 https://...

①leetcode 复习：81-90 股票最大值1 https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock/solution/gu-piao-1-by-19216801-eoq9/ 股票最大值2 https://leetcode-cn.com/problems/best-time-to-buy-and-sell-stock-ii/solution/mai-mai-gu-piao-2-by-19216801-wp59/ 股票最大值3 https://leetcode-cn.com/problems/best-time-to...

①leetcode 复习71-80 链接完全二叉树二叉树每层节点（递归或层次遍历） https://leetcode-cn.com/problems/populating-next-right-pointers-in-each-node/submissions/ 链接二叉树的每层节点（使用上一层的链表结构，层次遍历） https://leetcode-cn.com/problems/populating-next-right-pointers-in-each-node-ii/solution/lian-jie-er-cha-shu-mei-ceng-jie-dian-by-0fnk/ 杨辉三角...

①leetcode 复习：61-70 二叉树最小深度： https://leetcode-cn.com/problems/minimum-depth-of-binary-tree/ 二叉树路径和 https://leetcode-cn.com/problems/path-sum/solution/ 回溯法找所有路径 https://leetcode-cn.com/problems/path-sum-ii/submissions/ 二叉树展开成链表 https://leetcode-cn.com/problems/flatten-binary-tree-to-linked-list/submis...

①leetcode 复习第51-60题 中序及后序构造二叉树 https://leetcode-cn.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal/solution/zhong-xu-hou-xu-gou-zao-er-cha-shu-by-19-ka1t/ 层次遍历2 https://leetcode-cn.com/problems/binary-tree-level-order-traversal-ii/solution/ceng-ci-bian-li-bian-xing-by-1921680...

①leetcode 镜像二叉树 https://leetcode-cn.com/problems/symmetric-tree/solution/jing-xiang-er-cha-shu-by-19216801-u55v/ 广度遍历二叉树 https://leetcode-cn.com/problems/binary-tree-level-order-traversal/solution/yan-du-bian-li-er-cha-shu-by-19216801-n7ms/ 之字遍历 https://leetcode-cn.com/problems/binary-tree-zigzag-le...

①leetcode 复习40-50题 新做96-100题 交错字符串 https://leetcode-cn.com/problems/interleaving-string/solution/jiao-cuo-zi-fu-chuan-by-19216801-qgzz/ 卡特兰数求搜索数数量 https://leetcode-cn.com/problems/unique-binary-search-trees/ 验证二叉搜索数 https://leetcode-cn.com/problems/validate-binary-search-tree/ 恢复二叉搜索数 https://leetco...

①leetcode 最大括号匹配 91-95 dp，栈，正逆向匹配 https://leetcode-cn.com/problems/longest-valid-parentheses/ 解码方式 递归转dp，dp再进行优化。 https://leetcode-cn.com/problems/decode-ways/ 反转链表 https://leetcode-cn.com/problems/reverse-linked-list-ii/solution/fan-zhuan-lian-biao-by-19216801-kux2/ 回溯复原ip https://leetcode-cn.com/p...

①leetcode 86-90 两个没做出来的题： 1，扰乱字符串： https://leetcode-cn.com/problems/scramble-string/ 2，格雷编码： https://leetcode-cn.com/problems/gray-code/ 数组和链表已经基本熟练了，一般就是多指针、逆置等。链表建一个头节点可以省去很多判断，要舍得用引用。回溯和递归的中等题目也都可以写出来了。 dp真的是没有上限，很多题都反应不过来是dp，需要抽空专项训练一下。 ②剑指offer： 栈的推入弹出、二叉树层次遍历、之字遍历（用两个栈，进行每一个层次的遍历）、判断是否是先中后序遍...