【LeetCode】C# 90、Subsets II

Given a collection of integers that might contain duplicates, nums, return all possible subsets.

Note: The solution set must not contain duplicate subsets.

For example,
If nums = [1,2,2], a solution is:

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

给定数集，返回所有子集。
思路：DP。同一层遇到相同的数字时跳过，进入下一循环。

public class Solution {    public List<List<int>> SubsetsWithDup(int[] nums) {        List<List<int>> res = new List<List<int>>();            Array.Sort(nums);            List<int> temp = new List<int>();            subset(res,temp , nums, 0);            return res;        }        public static void subset(List<List<int>> res, List<int> temp, int[] nums, int start)        {            if (start == nums.Length+1) return;            res.Add(new List<int>(temp));            int i = start;            while (i < nums.Length)            {                temp.Add(nums[i]);                subset(res, temp, nums, i + 1);                temp.RemoveAt(temp.Count - 1);                i++;                while (i < nums.Length && nums[i] == nums[i - 1]) { i++; }            }        }    }