LeetCode90:Subsets II

Given a collection of integers that might contain duplicates, 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 = [1,2,2], a solution is:

这道题是求子集Subsets的更一般的情况，即给定的集合中存在重复的情况，可以使用Combination Sum II 相同的方法来消除重复元素。

做到现在发现好多题目都是触类旁通的了。

runtime:8ms

class Solution {public:    vector<vector<int>> subsetsWithDup(vector<int>& nums) {            vector<int> path;            vector<vector<int>> result;            result.push_back(path);            sort(nums.begin(),nums.end());            helper(nums,0,path,result);            return result;    }    void helper(vector<int> &nums,int pos,vector<int>& path,vector<vector<int>> &result)    {        if(pos==nums.size())            return ;        for(int i=pos;i<nums.size();i++)        {            path.push_back(nums[i]);            result.push_back(path);            helper(nums,i+1,path,result);            path.pop_back();            while(nums[i]==nums[i+1]) i++;        }    }};