【LeetCode】Number of Islands】的更多相关文章

Given a 2d grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by…
Number of Islands 问题描写叙述 Given a 2d grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the gr…
题目描述: Write a function that takes an unsigned integer and returns the number of '1' bits it has (also known as the Hamming weight). For example, the 32-bit integer '11' has binary representation 00000000000000000000000000001011, so the function shoul…
做太多遍了,秒杀. class Solution { public: int hammingWeight(uint32_t n) { ; ), num++); return num; } };…
[101]Symmetric Tree 判断一棵树是不是对称. 题解:直接递归判断了,感觉和bfs没有什么强联系,当然如果你一定要用queue改写的话,勉强也能算bfs. // 这个题目的重点是 比较对象是 左子树的左儿子和右子树的右儿子, 左子树的右儿子和右子树的左儿子.不要搞错. // 直接中序遍历的话会有错的情况,最蠢的情况是数字标注改一改.. /** * Definition for a binary tree node. * struct TreeNode { * int val; *…
链接:https://leetcode.com/tag/union-find/ [128]Longest Consecutive Sequence  (2018年11月22日,开始解决hard题) 给了一个无序的数组,问这个数组里面的元素(可以重新排序)能组成的最长的连续子序列是多长.本题的时间复杂度要求是 O(N). 本题 array 专题里面有, 链接:https://www.cnblogs.com/zhangwanying/p/9610923.html ,用个 hashmap 可以做到 O…
[98]Validate Binary Search Tree [99]Recover Binary Search Tree [100]Same Tree [101]Symmetric Tree [104]Maximum Depth of Binary Tree [105]Construct Binary Tree from Preorder and Inorder Traversal [106]Construct Binary Tree from Inorder and Postorder T…
[LeetCode]Largest Number 解题报告 标签(空格分隔): LeetCode 题目地址:https://leetcode.com/problems/largest-number/#/description 题目描述: Given a list of non negative integers, arrange them such that they form the largest number. For example, given [3, 30, 34, 5, 9], t…
[LeetCode]375. Guess Number Higher or Lower II 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/guess-number-higher-or-lower-ii/description/ 题目描述: We are playing the Guess Game. The game is as f…
[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]137. Single Number II 解题报告(Python) 标签: LeetCode 题目地址:https://leetcode.com/problems/single-number-ii/description/ 题目描述: Given an array of integers, every element appears three times except for one, which appears exactly once. Find that singl…
[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]452. Minimum Number of Arrows to Burst Balloons 解题报告(Python) 标签(空格分隔): LeetCode 题目地址:https://leetcode.com/problems/minimum-number-of-arrows-to-burst-balloons/description/ 题目描述: There are a number of spherical balloons spread in two-dimensio…
[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…
题目等级:Easy 题目描述: Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward. Example 1: Input: 121 Output: true Example 2: Input: -121 Output: false Explanation: From left to right, it reads -12…
题目如下: 解题思路:几乎和[leetcode]719. Find K-th Smallest Pair Distance 的方法一样.只不过一个是减法一个是乘法,还有一点区别是[leetcode]719. Find K-th Smallest Pair Distance中i-j和j-i只算一个元素,而本题中i*j与j*i算两个元素. 代码如下: class Solution(object): def findKthNumber(self, m, n, k): """ :ty…
[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…
[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…
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…
Algorithm [leetcode]893. Groups of Special-Equivalent Strings https://leetcode.com/problems/groups-of-special-equivalent-strings/ 1)problem You are given an array A of strings. Two strings S and T are special-equivalent if after any number of moves,…
题目如下: An integer has sequential digits if and only if each digit in the number is one more than the previous digit. Return a sorted list of all the integers in the range [low, high] inclusive that have sequential digits. Example 1: Input: low = 100,…
[600] Non-negative Integers without Consecutive Ones [629] K Inverse Pairs Array [638] Shopping Offers [639] Decode Ways II [646] Maximum Length of Pair Chain [647] Palindromic Substrings 给定一个字符串,判断有多少子串是 palindromic 的,子串就算所有字母都相同,但是开始和结束位置的下标不同,也算不同…
[78]Subsets 给了一个 distinct 的数组,返回它所有的子集. Example: Input: nums = [,,] Output: [ [], [], [], [,,], [,], [,], [,], [] ] 题解:我是直接dfs(backtracking)了,有个小地方写错了(dfs那里),至少调整了十多分钟,下次不要写错了. class Solution { public: vector<vector<int>> subsets(vector<int…
题目如下: Given an array of scores that are non-negative integers. Player 1 picks one of the numbers from either end of the array followed by the player 2 and then player 1 and so on. Each time a player picks a number, that number will not be available f…
题目如下: We are given a linked list with head as the first node.  Let's number the nodes in the list: node_1, node_2, node_3, ... etc. Each node may have a next larger value: for node_i, next_larger(node_i) is the node_j.val such that j > i, node_j.val…
[LeetCode]Island Perimeter 解题报告 [LeetCode] https://leetcode.com/problems/island-perimeter/ Total Accepted: 16143 Total Submissions: 28552 Difficulty: Easy Question You are given a map in form of a two-dimensional integer grid where 1 represents land…
[LeetCode]01 Matrix 解题报告 标签(空格分隔): LeetCode 题目地址:https://leetcode.com/problems/01-matrix/#/description 题目描述: Given a matrix consists of 0 and 1, find the distance of the nearest 0 for each cell. The distance between two adjacent cells is 1. Example:…
[LeetCode]376. Wiggle Subsequence 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/wiggle-subsequence/description/ 题目描述: A sequence of numbers is called a wiggle sequence if the differences betw…
[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]299. Bulls and Cows 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/bulls-and-cows/description/ 题目描述: You are playing the following Bulls and Cows game with your friend: You write down…