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], ] 要求 给定两个整数(n,k),返回长度为k,从1到n的所有组合(注意1.组合没有顺序  2. [2,3]和[3,2]为同一组,取前者小…

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], ] 方法1:把用queue实现bfs,改为用vector自己实现bfs,没有用额外的内存来存储中间值,但是时间上会Time Limite…

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 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…

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,…

称号 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(点我) 解题思路 组合问题,老思路---递归加循环,这个是组合里面比較简单的. 代码实现 class Solutio…

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…

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], ] 题意:给定1...n个数,求出每k个数的组合情况. 思路:使用DFS.定义中间数组变量,每当其大小为k时,将其存入结果res:若不等于…

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], ] Hide Tags Backtracking   这题是回溯题目,做好递归控制便可以了.   #include <iostream>…

You are climbing a stair case. It takes n steps to reach to the top. Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top? Note: Given n will be a positive integer. 题目分析:每次只能走1或2步,问n步的话有多少中走法???? 可以用动态规划和递归解…