标签：style blog io color os sp for strong on
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], ]
思路：
dfs搜索所有可行解。这里[1,2]和[2,1]算一个解，所以后面的数一定越来越大。
题解：
class Solution { public: vector<vector<int> > res; vector<int> tmp; void dfs(int n, int k, int t) { if(k==0) { res.push_back(tmp); return; } for(int i=t+1;i<=n;i++) { tmp.push_back(i); dfs(n,k-1,i); tmp.pop_back(); } } vector<vector<int> > combine(int n, int k) { if(k==0) return res; for(int i=1;i<=n;i++) { tmp.push_back(i); dfs(n,k-1,i); tmp.pop_back(); } return res; } };
标签：style blog io color os sp for strong on
原文地址：http://www.cnblogs.com/jiasaidongqi/p/4167213.html
