Given two integers n and k, return all possible combinations of k numbers out of 1 ... n. For example,If n = 4 and k = 2, a solution is: [ [2,4], [3,4], [2,3], [1,2], [1,3], [1,4], ]   Summary: recursive functions class Solution { public: vector<vect…

Given two integers n and k, return all possible combinations of k numbers out of 1 ... n. For example,If n = 4 and k = 2, a solution is: [ [2,4], [3,4], [2,3], [1,2], [1,3], [1,4], ] 题目大意:给两个数n和k,输出所有长度为k的排列组合. 解题思路:当做求子集来做,大于k的剪枝剪掉,最后再筛一下结果集. public…

题目: Given two integers n and k, return all possible combinations of k numbers out of 1 ... n. For example, If n = 4 and k = 2, a solution is: [ [2,4], [3,4], [2,3], [1,2], [1,3], [1,4], ] 题解: 这道题就是用DFS(参考Work BreakII)的                      res.add(  …

最近在准备找工作的算法题,刷刷LeetCode,以下是我的解题报告索引,每一题几乎都有详细的说明,供各位码农参考.根据我自己做的进度持续更新中......                              本文地址 LeetCode:Reverse Words in a String LeetCode:Evaluate Reverse Polish Notation LeetCode:Max Points on a Line LeetCode:Sort List LeetCode:Ins…

Here is my collection of solutions to leetcode problems. Related code can be found in this repo: https://github.com/zhuli19901106/leetcode LeetCode - Course Schedule LeetCode - Reverse Linked List LeetCode - Isomorphic Strings LeetCode - Count Primes…

Numbers can be regarded as product of its factors. For example, 8 = 2 x 2 x 2; = 2 x 4. Write a function that takes an integer n and return all possible combinations of its factors. Note: Each combination's factors must be sorted ascending, for examp…

Given two integers n and k, return all possible combinations of k numbers out of 1 ... n. For example,If n = 4 and k = 2, a solution is: [ [2,4], [3,4], [2,3], [1,2], [1,3], [1,4], ] 这道题让求1到n共n个数字里k个数的组合数的所有情况,还是要用深度优先搜索DFS来解,根据以往的经验,像这种要求出所有结果的集合,一般…

Given a digit string, return all possible letter combinations that the number could represent. A mapping of digit to letters (just like on the telephone buttons) is given below. Input:Digit string "23" Output: ["ad", "ae", &q…

原题链接在这里:https://leetcode.com/problems/factor-combinations/ 题目: Numbers can be regarded as product of its factors. For example, 8 = 2 x 2 x 2; = 2 x 4. Write a function that takes an integer n and return all possible combinations of its factors. Note:…

1 题目: Given a digit string, return all possible letter combinations that the number could represent. A mapping of digit to letters (just like on the telephone buttons) is given below. Input:Digit string "23" Output: ["ad", "ae&quo…

# -*- coding: utf8 -*-'''__author__ = 'dabay.wang@gmail.com' 17: Letter Combinations of a Phone Numberhttps://oj.leetcode.com/problems/letter-combinations-of-a-phone-number/ Given a digit string, return all possible letter combinations that the numbe…

Given two integers n and k, return all possible combinations of k numbers out of 1 ... n. For example, If n = 4 and k = 2, a solution is: [ [2,4], [3,4], [2,3], [1,2], [1,3], [1,4], ] 原题链接:https://oj.leetcode.com/problems/combinations/ 题目:给定两个整数n和k,返…

一天一道LeetCode 本系列文章已全部上传至我的github,地址:ZeeCoder's Github 欢迎大家关注我的新浪微博,我的新浪微博 欢迎转载,转载请注明出处 (一)题目 Given two integers n and k, return all possible combinations of k numbers out of 1 - n. For example, If n = 4 and k = 2, a solution is: [ [2,4], [3,4], [2,3]…

一天一道LeetCode (一)题目 Given a digit string, return all possible letter combinations that the number could represent. A mapping of digit to letters (just like on the telephone buttons) is given below. Input:Digit string "23" Output: ["ad",…

import java.util.ArrayList; import java.util.Arrays; import java.util.List; /** * Source : https://oj.leetcode.com/problems/combinations/ * * * Given two integers n and k, return all possible combinations of k numbers out of 1 ... n. * * For example,…

原题地址:https://oj.leetcode.com/problems/combinations/ 题意:组合求解问题. 解题思路:这种求组合的问题,需要使用dfs来解决. 代码: class Solution: # @return a list of lists of integers def combine(self, n, k): def dfs(start, valuelist): if self.count == k: ret.append(valuelist); return f…

题目: Given a digit string, return all possible letter combinations that the number could represent. A mapping of digit to letters (just like on the telephone buttons) is given below. Input:Digit string "23" Output: ["ad", "ae"…

题目链接:https://leetcode.com/problems/combinations/#/description    Problem:给两个正数分别为n和k,求出从1,2.......n这n个数字选择k个数字作为一个组合,求出所有的组合.   数学问题:排列组合问题,可以得到这样的组合个数为:C(n,k)     代码实现:递归程序实现. 从1开始遍历到n为止,中间使用tempList保存每一个组合,只有当这个tempList的长度等于k时,将这个tempList添加到ans中.  …

目录 题目链接 注意点 解法 小结 题目链接 Letter Combinations of a Phone Number - LeetCode 注意点 可以不用按字典序排序 解法 解法一:输入的数字逐个处理,在已经生成的字符串后面追加该当前数字对应的所有字符.时间复杂度为O(n) class Solution { public: vector<string> letterCombinations(string digits) { vector<string> ans,temp_an…

乘风破浪:LeetCode真题_017_Letter Combinations of a Phone Number 一.前言 如何让两个或者多个集合中的随机挑选的元素结合到一起,并且得到所有的可能呢?我们可能事先并不知道会用到哪几个集合,因此我们可以通过递归方法来解决. 二.Letter Combinations of a Phone Number 2.1 问题 2.2 分析和解决 通过上面的题目,我们基本上可以理解题意了,但是我们要怎么去处理呢,这个时候就需要用到递归算法了. public c…

Given two integers n and k, return all possible combinations of k numbers out of 1 ... n. For example,If n = 4 and k = 2, a solution is: [ [2,4], [3,4], [2,3], [1,2], [1,3], [1,4], ] 解题思路: 实现"combination组合"(类比"permutation排列",见Leetcode:…

1.  Container With Most Water Given n non-negative integers a1, a2, ..., an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of line i is at (i, ai) and (i, 0). Find two lines, which togethe…

Leetcode之回溯法专题-77. 组合(Combinations)   给定两个整数 n 和 k,返回 1 ... n 中所有可能的 k 个数的组合. 示例: 输入: n = 4, k = 2 输出: [ [2,4], [3,4], [2,3], [1,2], [1,3], [1,4], ] 分析:这题很简单,回溯取还是不取就行了. AC代码: class Solution { List<List<Integer>> ans = new ArrayList<>();…

[Leetcode]17. 电话号码的字母组合(Letter Combinations of a Phone Number) 题目描述: 给定一个仅包含数字 2-9 的字符串,返回所有它能表示的字母组合. 给出数字到字母的映射如下(与电话按键相同).注意 1 不对应任何字母. 示例: 输入:"23"输出:["ad", "ae", "af", "bd", "be", "bf&qu…

Given a string containing digits from 2-9inclusive, return all possible letter combinations that the number could represent. A mapping of digit to letters (just like on the telephone buttons) is given below. Note that 1 does not map to any letters. E…

Given two integers n and k, return all possible combinations of k numbers out of 1 ... n. For example,If n = 4 and k = 2, a solution is: [ [2,4], [3,4], [2,3], [1,2], [1,3], [1,4], ] 给两个数字n, k,返回所有由[1...n]中的k数字组合的可能解. 解法1: 递归 解法2: 迭代 C++: Recursion c…

Numbers can be regarded as product of its factors. For example, 8 = 2 x 2 x 2; = 2 x 4. Write a function that takes an integer n and return all possible combinations of its factors. Note: Each combination's factors must be sorted ascending, for examp…

作者: 负雪明烛 id: fuxuemingzhu 个人博客:http://fuxuemingzhu.cn/ 个人公众号:负雪明烛 本文关键词:电话号码, 字母组合,回溯法,题解,leetcode, 力扣,Python, C++, Java 目录 题目描述 题目大意 解题方法 回溯法 内置函数 循环 日期 题目地址:https://leetcode.com/problems/generate-parentheses/description/ 题目描述 Given a string contain…

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/combinations/description/ 题目描述 Given two integers n and k, return all possible combinations of k numbers out of 1 - n. For…

Numbers can be regarded as product of its factors. For example, 8 = 2 x 2 x 2; = 2 x 4. Write a function that takes an integer n and return all possible combinations of its factors. Note: You may assume that n is always positive. Factors should be gr…