标签：style blog io color ar os sp for div
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], ]
Solution:
public class Solution { public List<List<Integer>> combine(int n, int k) { List<List<Integer>> result = new ArrayList<List<Integer>>(); List<Integer> temp = new ArrayList<Integer>(); dfs(n, k, 0, 1, result, temp); return result; } private void dfs(int n, int k, int step, int start, List<List<Integer>> result, List<Integer> temp) { // TODO Auto-generated method stub if (step > k) return; if (step == k) { result.add(new ArrayList<Integer>(temp)); return; } for(int i=start;i<=n;++i){ temp.add(i); dfs(n, k, step+1, i+1, result, temp); temp.remove(temp.size()-1); } } }
标签：style blog io color ar os sp for div
原文地址：http://www.cnblogs.com/Phoebe815/p/4093967.html
