Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have exactly one solution, and you may not use the same element twice. Example: Given nums = [2, 7, 11, 15]…

题目如下: 解题思路:本题是[leetcode]473. Matchsticks to Square的姊妹篇,唯一的区别是[leetcode]473. Matchsticks to Square指定了分成四个子数组,而本题分成的份数不定,作为参数输入.另外,本题的测试用例好像复杂一点,因此我过滤掉了nums中值等于avg的元素,不参与后面的DFS计算,提高效率. 代码如下: class Solution(object): def canPartitionKSubsets(self, nums,…

[LeetCode]129. Sum Root to Leaf Numbers 解题报告(Python) 标签(空格分隔): LeetCode 题目地址:https://leetcode.com/problems/sum-root-to-leaf-numbers/description/ 题目描述: Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a numbe…

[LeetCode]813. Largest Sum of Averages 解题报告(Python) 标签(空格分隔): LeetCode 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 题目地址:https://leetcode.com/problems/largest-sum-of-averages/description/ 题目描述: We partition a row of numbers A into at most…

[LeetCode]113. Path Sum II 解题报告(Python) 标签(空格分隔): LeetCode 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.me/ 题目地址:https://leetcode.com/problems/path-sum-ii/description/ 题目描述: Given a binary tree and a sum, find all root-to-leaf paths where each…

题目如下: 解题思路:本题和[leetcode]583. Delete Operation for Two Strings 类似,区别在于word1[i] != word2[j]的时候,是删除word1[i]还是word2[j]取决于min(dp[i-1][j]+ord(word1[i-1]),dp[i][j-1]+ord(word2[j-1])). 代码如下: class Solution(object): def minimumDeleteSum(self, s1, s2): ""…

题目如下: 解题思路:我的想法对于数组中任意一个元素,找出其左右两边最近的小于自己的元素.例如[1,3,2,4,5,1],元素2左边比自己小的元素是1,那么大于自己的区间就是[3],右边的区间就是[4,5].那么对于元素2来说,和左边区间合并组成[2,3]以及和右边区间合并组成[2,4,5],这两段区间包括2在内的所有subarray的最小值都是2,其分别可以组成的subarry的个数是 len([3])和len([4,5]),左右区间合并在一起可以组成的subarray的个数是len([3])…

53. Maximum Subarray[leetcode] Find the contiguous subarray within an array (containing at least one number) which has the largest sum. For example, given the array [-2,1,-3,4,-1,2,1,-5,4],the contiguous subarray [4,-1,2,1] has the largest sum = 6. 挑…

题目等级:4Sum(Medium) 题目描述: Given an array nums of n integers and an integer target, are there elements a, b, c, and d in nums such that a + b + c + d = target? Find all unique quadruplets in the array which gives the sum of target. Note: The solution se…

题目等级:3Sum(Medium) 题目描述: Given an array nums of n integers, are there elements a, b, c in nums such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero. Note: The solution set must not contain duplicate triplets. Exam…

链接:https://leetcode.com/tag/binary-search-tree/ [220]Contains Duplicate III (2019年4月20日) (好题) Given an array of integers, find out whether there are two distinct indices i and j in the array such that the absolute difference between nums[i] and nums[…

[2]Add Two Numbers (2018年12月23日,review) 链表的高精度加法. 题解:链表专题:https://www.cnblogs.com/zhangwanying/p/9797184.html [7]Reverse Integer (2018年12月23日, review) 给了一个32位的整数,返回它的reverse后的整数.如果reverse后的数超过了整数的范围,就返回 0. Example 1: Input: 123 Output: 321 Example 2:…

[1]Two Sum (2018年11月9日,k-sum专题,算法群衍生题) 给了一个数组 nums, 和一个 target 数字,要求返回一个下标的 pair, 使得这两个元素相加等于 target . 题解:我这次最大范围的优化代码, hash-table + one pass,时间复杂度 O(N),空间复杂度 O(N).重点在于动态找,一边生成hash-table的同时去找答案,不是先生成hash-table再开始找答案. //这种类似 hash 的能用 unordered_map 就不要…

[94]Binary Tree Inorder Traversal [95]Unique Binary Search Trees II (2018年11月14日,算法群) 给了一个 n,返回结点是 1 - n 的所有形态的BST. 题解:枚举每个根节点 r, 然后递归的生成左右子树的所有集合,然后做笛卡尔积. /** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * Tr…

题目如下: Given an array A of positive integers, A[i]represents the value of the i-th sightseeing spot, and two sightseeing spots i and j have distance j - i between them. The score of a pair (i < j) of sightseeing spots is (A[i] + A[j] + i - j) : the su…

作者: 负雪明烛 id: fuxuemingzhu 个人博客:http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 BFS 日期 题目地址:https://leetcode-cn.com/problems/ji-qi-ren-de-yun-dong-fan-wei-lcof/ 题目描述 地上有一个m行n列的方格,从坐标 [0,0] 到坐标 [m-1,n-1] .一个机器人从坐标 [0, 0] 的格子开始移动,它每次可以向左.右.上.下移动一格(不能移动到方格外),也…

目录 二分查找 排序的写法 BFS的写法 DFS的写法 回溯法 树 递归 迭代 前序遍历 中序遍历 后序遍历 构建完全二叉树 并查集 前缀树 图遍历 Dijkstra算法 Floyd-Warshall算法 Bellman-Ford算法 最小生成树 Kruskal算法 Prim算法 拓扑排序 双指针 动态规划 状态搜索 贪心 本文的目的是收集一些典型的题目,记住其写法,理解其思想,即可做到一通百通.欢迎大家提出宝贵意见! 博主有算法题解的微信公众号啦,欢迎关注「负雪明烛」,持续更新算法题的解题思路…

[LeetCode]657. Judge Route Circle 标签(空格分隔): LeetCode 题目地址:https://leetcode.com/problems/judge-route-circle/description/ 题目描述: Initially, there is a Robot at position (0, 0). Given a sequence of its moves, judge if this robot makes a circle, which mea…

[LeetCode]120. Triangle 解题报告(Python) 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 题目地址https://leetcode.com/problems/triangle/description/ 题目描述: Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjac…

[LeetCode]792. Number of Matching Subsequences 解题报告(Python) 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 题目地址:https://leetcode.com/problems/number-of-matching-subsequences/description/ 题目描述: Given string S and a dictionary of words words,…

[LeetCode]881. Boats to Save People 解题报告(Python) 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 题目地址:https://leetcode.com/problems/boats-to-save-people/description/ 题目描述: The i-th person has weight people[i], and each boat can carry a maximu…

[LeetCode]486. Predict the Winner 解题报告(Python) 标签(空格分隔): LeetCode 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 题目地址:https://leetcode.com/problems/predict-the-winner/description/ 题目描述: Given an array of scores that are non-negative integers…

[LeetCode]373. Find K Pairs with Smallest Sums 解题报告(Python) 标签: LeetCode 题目地址:https://leetcode.com/problems/find-k-pairs-with-smallest-sums/description/ 题目描述: You are given two integer arrays nums1 and nums2 sorted in ascending order and an integer k…

[LeetCode]227. Basic Calculator II 解题报告(Python) 标签(空格分隔): LeetCode 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.me/ 题目地址:https://leetcode.com/problems/basic-calculator-ii/description/ 题目描述: Implement a basic calculator to evaluate a simple exp…

[LeetCode]306. Additive Number 解题报告(Python) 标签(空格分隔): LeetCode 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.me/ 题目地址:https://leetcode.com/problems/additive-number/description/ 题目描述: Additive number is a string whose digits can form additive se…

[LeetCode]848. Shifting Letters 解题报告(Python) 标签(空格分隔): LeetCode 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.me/ 题目地址:https://leetcode.com/problems/shifting-letters/description/ 题目描述: We have a string S of lowercase letters, and an integer arr…

[LeetCode]554. Brick Wall 解题报告(Python) 标签(空格分隔): LeetCode 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.me/ 题目地址:https://leetcode.com/problems/brick-wall/description/ 题目描述: There is a brick wall in front of you. The wall is rectangular and has…

[LeetCode]673. Number of Longest Increasing Subsequence 解题报告(Python) 标签(空格分隔): LeetCode 题目地址:https://leetcode.com/problems/number-of-longest-increasing-subsequence/description/ 题目描述: Given an unsorted array of integers, find the number of longest inc…

[LeetCode]Minimum Depth of Binary Tree Given a binary tree, find its minimum depth. The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node. 递归和非递归,此提比较简单.广度优先遍历即可.关键之处就在于如何保持访问深度. 下面是4种代码: im…

Given an index k, return the kth row of the Pascal's triangle. For example, given k = 3, Return [1,3,3,1]. Note: Could you optimize your algorithm to use only O(k) extra space? 思路:最简单的方法就是依照[Leetcode]Pascal's Triangle 的方式自顶向下依次求解,但会造成空间的浪费.若仅仅用一个vect…