[LeetCode] Subsets

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],

[]

]

Discuss

java code :

public class Solution {  
    public ArrayList<ArrayList<Integer>> subsets(int[] S) {  
        // IMPORTANT: Please reset any member data you declared, as  
        // the same Solution instance will be reused for each test case.  
        ArrayList<ArrayList<Integer>> res = new ArrayList<ArrayList<Integer>>();  
        res.add(new ArrayList<Integer>());  
        if(S.length ==0)  
            return res;  
        Arrays.sort(S);  
        ArrayList<Integer> tmp = new ArrayList<Integer>();  
        for(int i = 1; i <= S.length; i++)  
        {  
            tmp.clear();  
            recursion(res,tmp,i,S,0);  
        }  
        return res;  
    }  
    public void recursion(ArrayList<ArrayList<Integer>> res, ArrayList<Integer> tmp, int k, int[] S, int dp)  
    {  
        if(k == tmp.size())  
        {  
            res.add(new ArrayList<Integer>(tmp));  
            return ;  
        }  
        for(int i = dp; i < S.length; i++)  
        {  
            tmp.add(S[i]);  
            recursion(res,tmp,k,S,i+1);  
            tmp.remove(tmp.size() - 1);  
        }  
    }  
}

补充：综合编程 , 其他综合 ,