Word Break II Given a string s and a dictionary of words dict, add spaces in s to construct a sentence where each word is a valid dictionary word. Return all such possible sentences. For example, givens = "catsanddog",dict = ["cat", &q…

Given a string s and a dictionary of words dict, add spaces in s to construct a sentence where each word is a valid dictionary word. Return all such possible sentences. For example, givens = "catsanddog",dict = ["cat", "cats"…

Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words. For example, givens = "leetcode",dict = ["leet", "code"]. Return true because &…

Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words. For example, given s = "leetcode", dict = ["leet", "code"]. Return true because…

  Word Ladder II Given two words (start and end), and a dictionary, find all shortest transformation sequence(s) from start to end, such that: Only one letter can be changed at a time Each intermediate word must exist in the dictionary For example, G…

Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words. For example, givens = "leetcode",dict = ["leet", "code"]. Return true because &…

思路是这种.我们从第一个字符開始向后依次找,直到找到一个断句的地方,使得当前获得的子串在dict中,若找到最后都没找到.那么就是False了. 在找到第一个后,接下来找下一个断句处,当然是从第一个断句处的下一个字符開始找连续的子串,可是这时与第一个就稍有不同.比方说word='ab', dict={ 'a', ab', ...},在找到a后,接下来处理的是b.我们发现b不在dict中,可是我们发现b能够和a结合,形成ab,而ab在dict中.所以这里的每一个子串就能够有三种选择.要么自己单独作为…

Given a 2D board and a list of words from the dictionary, find all words in the board. Each word must be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same le…

Given two words (start and end), and a dictionary, find all shortest transformation sequence(s) from start to end, such that: Only one letter can be changed at a time Each intermediate word must exist in the dictionary For example, Given:start = "hit…

Word Break II 题解 题目来源:https://leetcode.com/problems/word-break-ii/description/ Description Given a non-empty string s and a dictionary wordDict containing a list of non-empty words, add spaces in s to construct a sentence where each word is a valid d…

Given a non-empty string s and a dictionary wordDict containing a list of non-empty words, add spaces in s to construct a sentence where each word is a valid dictionary word. Return all such possible sentences. Note: The same word in the dictionary m…

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 方法一:递归 方法二:回溯法 日期 题目地址:https://leetcode.com/problems/permutations-ii/description/ 题目描述 Given a collection of numbers that might contain duplicates, return all possible unique p…

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 递归 回溯法 日期 题目地址:https://leetcode.com/problems/subsets-ii/description/ 题目描述 Given a collection of integers that might contain duplicates, nums, return all possible subsets (the po…

Problem link: http://oj.leetcode.com/problems/word-break-ii/ This problem is some extension of the word break problem, so the solution is based on the discussion in Word Break. We also use DP to solve the problem. In this solution, A[i] is not a bool…

[Description] Given an array of integers that is already sorted in ascending order, find two numbers such that they add up to a specific target number. The function twoSum should return indices of the two numbers such that they add up to the target,…

[问题]实现一个基本的计算器来计算一个简单的字符串表达式的值.字符串表达式仅包含非负整数,+, - ,*,/ 四种运算符和空格  .整数除法仅保留整数部分. 输入: "3+2*2" 输出: 示例 : 输入: " 3/2 " 输出: [思路] 总体思路来说,我们遍历字符串的每个字符,注意:加减乘除以及空格的ASCII码 < '0'.如果这个字符为数字字符,需要将两个非数字字符之间的不包含空格的字符串变换成数值!表达式:num = num * 10 - '0' +…

[问题]n 皇后问题研究的是如何将 n 个皇后放置在 n×n 的棋盘上,并且使皇后彼此之间不能相互攻击. 上图为 8 皇后问题的一种解法.给定一个整数 n,返回 n 皇后不同的解决方案的数量. 示例: 输入: 输出: 解释: 皇后问题存在如下两个不同的解法. [ [".Q..", // 解法 1 "…Q", "Q…", "..Q."], ["..Q.", // 解法 2 "Q…", &q…

[问题]给定一个非负整数数组,你最初位于数组的第一个位置.数组中的每个元素代表你在该位置可以跳跃的最大长度.你的目标是使用最少的跳跃次数到达数组的最后一个位置. 示例: 输入: [,,,,] 输出: 解释: 跳到最后一个位置的最小跳跃数是 . 从下标为 跳到下标为 的位置,跳 步,然后跳 步到达数组的最后一个位置. 说明: 假设你总是可以到达数组的最后一个位置 [思路]由于题目中规定总能到达数组的最后一个位置,因此我们在遍历数组时每次都要去找最大的跳跃位置,只有到达了这个最远的边界end,我们才…

[题意] 输出N皇后问题的解法个数. [题解] 解法一:传统dfs回溯,模拟Q放置的位置即可,应该不难,虽然能通过,但是时间复杂度很高. 解法二:位运算大法好! 首先要明白这道题里两个核心的位运算 1.x & -x 代表除最后一位 1 保留,其它位全部为 0(这个是不是很熟悉,就是树状数组的lowbit哦) 这里要明白计算机存储数的时候存储的是补码,假设x为0101000,正数的补码还是正数,-x为1101000,其补码为1011000,然后0101000 & 1011000,就是保留x的…

Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words. For example, givens = "leetcode",dict = ["leet", "code"]. Return true because &…

Subsets II Given a collection of integers that might contain duplicates, S, return all possible subsets. Note: Elements in a subset must be in non-descending order. The solution set must not contain duplicate subsets. For example,If S = [1,2,2], a so…

Word Ladder Total Accepted: 24823 Total Submissions: 135014My Submissions Given two words (start and end), and a dictionary, find the length of shortest transformation sequence from start to end, such that: Only one letter can be changed at a time Ea…

Combination Sum II Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. Each number in C may only be used once in the combination. Note: All numbers (including t…

Given a string s and a dictionary of words dict, add spaces in s to construct a sentence where each word is a valid dictionary word. Return all such possible sentences. For example, givens = "catsanddog",dict = ["cat", "cats"…

Spiral Matrix II Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order. For example,Given n = 3, You should return the following matrix: [ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ] ]   与Spiral Matrix类似:   class So…

Unique Paths II Total Accepted: 22828 Total Submissions: 81414My Submissions Follow up for "Unique Paths": Now consider if some obstacles are added to the grids. How many unique paths would there be? An obstacle and empty space is marked as 1 an…

Word Search Given a 2D board and a word, find if the word exists in the grid. The word can be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same letter cell m…

Path Sum II Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. For example:Given the below binary tree and sum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ / \ 7 2 5 1 return [ [5,4,11,2], [5,8,4,5] ]     采用深度…

Given a string s, partition s such that every substring of the partition is a palindrome. Return the minimum cuts needed for a palindrome partitioning of s. For example, given s = "aab",Return 1 since the palindrome partitioning ["aa",…

今天开始,回溯法强化阶段. Given a 2D board and a word, find if the word exists in the grid. The word can be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same letter cell…