Subsets

//Subsets My Submissions Question Solution 
//Total Accepted: 62243 Total Submissions: 219925 Difficulty: Medium
//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],
//  []
//]
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;


public class Subsets {


public static void main(String[] args) {
// TODO Auto-generated method stub


}
public List<List<Integer>> subsets(int[] nums) {
//先做排序
Arrays.sort(nums);
ArrayList<List<Integer>> result=new ArrayList<>();
int count=nums.length;
result.add(new ArrayList<Integer>());
//把每个元素加进来
for(int i=0;i<count;i++){
int length=result.size();
//不能使用迭代器的方式访问，出现并发修改异常，使用下标方式访问
for(int j=0;j<length;j++){
ArrayList<Integer> other=new ArrayList<>(result.get(j));
other.add(nums[i]);
result.add(other);
}
}
        return result;
    }
}