leetcode------Subsets
标题: | Subsets |
通过率: | 28.2% |
难度: | 中等 |
Given a set of distinct integers, 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 = [1,2,3]
, a solution is:
[ [3], [1], [2], [1,2,3], [1,3], [2,3], [1,2], [] ]
本题思路就是找出所有子集,具体看代码:
1 public class Solution { 2 public ArrayList<ArrayList<Integer>> subsets(int[] S) { 3 ArrayList<ArrayList<Integer>> res=new ArrayList<ArrayList<Integer>>(); 4 ArrayList<Integer> tmp=new ArrayList<Integer>(); 5 int[]num=S; 6 Arrays.sort(num); 7 dfs(res,tmp,0,num); 8 return res; 9 } 10 public void dfs(ArrayList<ArrayList<Integer>> res,ArrayList<Integer> tmp,int start,int[] num){ 11 if(!res.contains(tmp)) 12 res.add(new ArrayList<Integer>(tmp)); 13 for(int i=start;i<num.length;i++){ 14 tmp.add(num[i]); 15 dfs(res,tmp,i+1,num); 16 tmp.remove(tmp.size()-1); 17 } 18 } 19 }