[LeetCode]Subsets

Given a set of distinct integers, nums, 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 nums = 

[1,2,3]

, a solution
is:

[
[3],
[1],
[2],
[1,2,3],
[1,3],
[2,3],
[1,2],
[]
]

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题解:使用递归
code：
public class Solution {
public List<List<Integer>> subsets(int[] nums) {

Arrays.sort(nums);
List<List<Integer>> ans = new ArrayList<List<Integer>>();
List<Integer> res = new ArrayList<Integer>();
sovle(0, nums.length, nums, res, ans);
return ans;
}
private void sovle(int cur ,int length, int[] nums, List<Integer> res, List<List<Integer>> ans)
{
ans.add(new ArrayList<Integer>(res));
for(int i = cur; i<length; i++)
{
res.add(nums[i]);
sovle(i+1 ,length, nums, res, ans);
res.remove(res.size() - 1);
}
}
}