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leetcode 求众数
https://leetcode-cn.com/problems/majority-element/class Solution {public: int majorityElement(vector<int>& nums) { int times = 0; int ans = 0; for (in...原创 2019-10-27 14:42:06 · 140 阅读 · 0 评论 -
leetcode 220. 存在重复元素 III
https://leetcode-cn.com/problems/contains-duplicate-iii/方法1class Solution {public: bool containsNearbyAlmostDuplicate(vector<int>& nums, int k, int t) { if (t<0 || k ==0...原创 2019-10-26 20:11:51 · 132 阅读 · 0 评论 -
leetcode 173. 二叉搜索树迭代器
https://leetcode-cn.com/problems/binary-search-tree-iterator/两个栈class BSTIterator {public: BSTIterator(TreeNode* root) { inorder(root); dump_stack(); } /** @retu...原创 2019-10-25 22:03:27 · 159 阅读 · 0 评论 -
leetcode 162. 寻找峰值
https://leetcode-cn.com/problems/find-peak-element/官方解答遍历class Solution {public: int findPeakElement(vector<int>& nums) { for (int i = 0; i < nums.size() - 1; ++i) ...原创 2019-10-25 11:58:17 · 172 阅读 · 0 评论 -
leetcode 二叉树非递归遍历
https://leetcode-cn.com/problems/binary-tree-preorder-traversal/（前序遍历）class Solution {public: vector<int> preorderTraversal(TreeNode* root) { if (root == NULL) return {}; ...原创 2019-10-22 20:42:38 · 169 阅读 · 0 评论 -
leetcode 300. 最长上升子序列 334. 递增的三元子序列 354. 俄罗斯套娃信封问题
讲解：https://mp.weixin.qq.com/s/EWLi6sP3l4xsuc6GDpQAjwhttps://mp.weixin.qq.com/s/wK3zCwMtT04DdvTo-FzQ1Qhttps://leetcode-cn.com/problems/longest-increasing-subsequence/（LIS）O(N^2)解法class So...原创 2019-10-14 21:42:28 · 276 阅读 · 0 评论 -
leetcode 138. 复制带随机指针的链表
https://leetcode-cn.com/problems/copy-list-with-random-pointer/map法：class Solution {public: Node* copyRandomList(Node* head) { if (head == NULL) return NULL; map<...原创 2019-10-12 17:51:39 · 111 阅读 · 0 评论 -
leetcode 反转链表
https://leetcode-cn.com/problems/reverse-linked-list/（整体反转）迭代法class Solution {public: ListNode* reverseList(ListNode* head) { ListNode *prev = NULL; ListNode *cur = head; ...原创 2019-10-12 10:19:08 · 88 阅读 · 0 评论 -
leetcode 19. 删除链表的倒数第N个节点
https://leetcode-cn.com/problems/remove-nth-node-from-end-of-list/class Solution {public: ListNode* removeNthFromEnd(ListNode* head, int n) { if (head == NULL) return NULL; Li...原创 2019-10-03 16:23:43 · 81 阅读 · 0 评论 -
leetcode 4. 寻找两个有序数组的中位数
https://leetcode-cn.com/problems/median-of-two-sorted-arrays/看这个解答https://leetcode-cn.com/problems/median-of-two-sorted-arrays/solution/xiang-xi-tong-su-de-si-lu-fen-xi-duo-jie-fa-by-w-2/class ...原创 2019-10-03 19:56:25 · 80 阅读 · 0 评论 -
leetcode 115. 不同的子序列
https://leetcode-cn.com/problems/distinct-subsequences/https://leetcode.wang/leetcode-115-Distinct-Subsequences.html原创 2019-10-05 00:12:08 · 129 阅读 · 0 评论 -
leetcode 61. 旋转链表
https://leetcode-cn.com/problems/rotate-list/方法1（旋转数组法）/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(...原创 2019-10-07 23:28:11 · 102 阅读 · 0 评论 -
leetcode 不同路径
https://leetcode-cn.com/problems/unique-paths/class Solution {public: int uniquePaths(int m, int n) { int dp[m][n]; for (int i = 0; i < m; ++i) dp[i][0] = 1; ...原创 2019-10-07 23:43:06 · 111 阅读 · 0 评论 -
leetcode 74. 搜索二维矩阵
https://leetcode-cn.com/problems/search-a-2d-matrix/class Solution { public: bool searchMatrix(vector<vector<int>>& matrix, int target) { int m = matrix.size(); if (m ==...原创 2019-10-08 19:20:20 · 113 阅读 · 0 评论 -
leetcode 旋转排序数组
https://leetcode-cn.com/problems/search-in-rotated-sorted-array/查找特定数字，无重复数字class Solution {public: int search(vector<int>& nums, int target) { int left = 0; int ri...原创 2019-10-08 19:48:14 · 107 阅读 · 0 评论 -
leetcode 删除排序链表中的重复元素
https://leetcode-cn.com/problems/remove-duplicates-from-sorted-list/重复元素保留一个class Solution {public: ListNode* deleteDuplicates(ListNode* head) { ListNode *cur = head; while ...原创 2019-10-08 20:11:17 · 83 阅读 · 0 评论 -
leetcode 子集
https://leetcode-cn.com/problems/subsets/（无重复元素）class Solution {public: vector<vector<int>> subsets(vector<int>& nums) { vector<vector<int>> ans; ...原创 2019-10-08 23:01:40 · 111 阅读 · 0 评论 -
leetcode 组合&组合总和
https://leetcode-cn.com/problems/combination-sum/（无重复）class Solution {private: vector<int> candidates; vector<vector<int>> res; vector<int> path;public: vo...原创 2019-10-08 23:04:53 · 171 阅读 · 0 评论 -
leetcode 排列
https://leetcode-cn.com/problems/next-permutation/（下一个排列）class Solution {public: void nextPermutation(vector<int> &nums) { int i = (int)nums.size() - 2; while (i >...原创 2019-10-08 23:06:39 · 119 阅读 · 0 评论 -
leetcode 103. 二叉树的锯齿形层次遍历
https://leetcode-cn.com/problems/binary-tree-zigzag-level-order-traversal/剑指offer原题class Solution {public: vector<vector<int>> zigzagLevelOrder(TreeNode* root) { vector&l...原创 2019-10-09 15:13:32 · 102 阅读 · 0 评论 -
leetcode 二叉树的层次遍历
https://leetcode-cn.com/problems/binary-tree-level-order-traversal/(上到下)class Solution {public: vector<vector<int>> levelOrder(TreeNode* root) { vector<vector<int>...原创 2019-10-09 19:55:20 · 97 阅读 · 0 评论 -
leetcode 填充每个节点的下一个右侧节点指针
https://leetcode-cn.com/problems/populating-next-right-pointers-in-each-node-ii/（通用解）class Solution {public: Node* connect(Node* root) { Node *cur = root; while(cur) {...原创 2019-10-09 20:26:30 · 104 阅读 · 0 评论 -
leetcode 120. 三角形最小路径和
https://leetcode-cn.com/problems/triangle/二维dpclass Solution {public: int minimumTotal(vector<vector<int>>& triangle) { if (triangle.size() == 0) return 0; ...原创 2019-10-09 20:46:15 · 95 阅读 · 0 评论 -
leetcode 股票买卖问题
方法1：动态规划法https://mp.weixin.qq.com/s/voti73ay-Ko3mt0qwIDouQ核心思路是找出第一次卖在哪天是最佳的class Solution {public: int maxProfit(int k, vector<int>& prices) { return f(k, prices); ...原创 2019-09-22 13:09:01 · 296 阅读 · 0 评论 -
leetcode 34. 在排序数组中查找元素的第一个和最后一个位置
https://leetcode-cn.com/problems/find-first-and-last-position-of-element-in-sorted-array/两次二分查找class Solution { // returns leftmost (or rightmost) index at which `target` should be // ins...原创 2019-10-03 14:57:21 · 90 阅读 · 0 评论 -
leetcode 416. 分割等和子集
https://leetcode-cn.com/problems/partition-equal-subset-sum/0-1背包问题变形class Solution {public: bool canPartition(vector<int>& nums) { int sum = 0; for (auto n : nums)...原创 2019-10-02 20:25:24 · 148 阅读 · 0 评论 -
leetcode 686. 重复叠加字符串匹配
https://leetcode-cn.com/problems/repeated-string-match/submissions/方法一：这个问题可以概括为“最小的 k 是什么，B 是 A*k 的子串？”我们可以试试每一个 k。算法：假设我们写了 S = A+A+A+...,如果 B 是 S 的子串，我们只需要检查一些 S[0:], S[1:], ..., S[len(A) - ...原创 2019-09-28 11:04:32 · 226 阅读 · 0 评论 -
leetcode 680. 验证回文字符串 Ⅱ
https://leetcode-cn.com/problems/valid-palindrome-ii/submissions/方法二：贪心算法如果字符串的起始字符和结束字符相同（即 s[0]==s[s.length-1]），则内部字符是否为回文（s[1], s[2], ..., s[s.length - 2]）将唯一地确定整个字符串是否为回文。算法：假设我们想知道 s[i],s[i...原创 2019-09-28 10:26:27 · 108 阅读 · 0 评论 -
leetcode 1071. 字符串的最大公因子
https://leetcode-cn.com/problems/greatest-common-divisor-of-strings/submissions/基于一个事实：两个字符串的最大公因子的长度，必定是两个字符串长度的最大公约数，否则无法被除尽。于是解法步骤如下：1 求出两个字符串长度的最大公约数；2 其中一个字符串的前最大公约数个字符组成的字符串有可能是解；3 遍历两个字符串...原创 2019-09-27 23:07:06 · 334 阅读 · 1 评论 -
leetcode 459. 重复的子字符串
https://leetcode-cn.com/problems/repeated-substring-pattern/submissions/周期串解法:https://leetcode-cn.com/problems/repeated-substring-pattern/solution/cppjie-fa-zhou-qi-chuan-by-brianyi/原创 2019-09-27 20:31:18 · 120 阅读 · 0 评论 -
leetcode 23. 合并K个排序链表
https://leetcode-cn.com/problems/merge-k-sorted-lists/submissions/class Solution {public: class cmp{ public: bool operator()(ListNode*&a, ListNode*&b) { ...原创 2019-09-22 16:10:06 · 87 阅读 · 0 评论 -
leetcode 225. 用队列实现栈
https://leetcode-cn.com/problems/implement-stack-using-queues/方法（一个队列）：class MyStack { queue<int> nums;public: /** Initialize your data structure here. */ MyStack() { /...原创 2019-09-21 15:42:13 · 92 阅读 · 0 评论 -
leetcode 232. 用栈实现队列
https://leetcode-cn.com/problems/implement-queue-using-stacks/submissions/解法1（一个队列）：//把p1中的数据转移到p2中void change_stack_value(stack<int> *p1,stack<int> *p2){ int k=p1->size(); ...原创 2019-09-21 15:42:26 · 109 阅读 · 0 评论 -
leetcode 300. 最长递增子序列
https://leetcode-cn.com/problems/longest-increasing-subsequence/https://mp.weixin.qq.com/s/EWLi6sP3l4xsuc6GDpQAjw原创 2019-09-21 15:42:36 · 124 阅读 · 0 评论 -
leetcode 437. 路径总和 III
https://leetcode-cn.com/problems/path-sum-iii/submissions/思路 ：https://mp.weixin.qq.com/s/uPFWODEIbO2MORbA8v3cJw原创 2019-09-21 15:42:47 · 107 阅读 · 0 评论 -
leetcode 475. 供暖器
https://leetcode-cn.com/problems/heaters/submissions/https://blog.youkuaiyun.com/wlsk801/article/details/70306673思路：先将取暖器数组排序，在遍历所有house，对每个house，在取暖器数组中进行binary search，如果命中，则说明取暖器位置和house位置重合，这个hous...原创 2019-09-21 15:41:17 · 187 阅读 · 0 评论 -
leetcode 796. 旋转字符串
https://leetcode-cn.com/problems/rotate-string/submissions/思路：首先确认两个字符串的长度要相等。其次只要保证A+A 的字符串中包含B就可以了。因为A+A已经包含了所有可移动的方案。class Solution {public: bool rotateString(string A, string B) { ...原创 2019-09-29 11:28:33 · 104 阅读 · 0 评论 -
leetcode 1128. 等价多米诺骨牌对的数量
https://leetcode-cn.com/problems/number-of-equivalent-domino-pairs/submissions/这道题主要是边界条件多:bool cmp(const vector<int> &a, vector<int> &b){ //不能只考虑第一个元素 if (a[0] == b[...原创 2019-09-29 12:31:14 · 114 阅读 · 0 评论 -
leetcode 94. 二叉树的中序遍历
https://leetcode-cn.com/problems/binary-tree-inorder-traversal/submissions/递归法class Solution {public: vector<int> inorderTraversal(TreeNode* root) { vector<int> res; ...原创 2019-09-29 21:37:08 · 101 阅读 · 0 评论 -
leetcode 207. 课程表
https://leetcode-cn.com/problems/course-schedule/拓扑排序，判断有向无环图问题class Solution {public: class Graph{ public: Graph(int v) { this->v = v; adj.res...原创 2019-10-01 20:23:32 · 79 阅读 · 0 评论