LeetCode 47. Permutations II

Given a collection of numbers that might contain duplicates, return all possible unique permutations.

For example,

[1,1,2] have the following unique permutations:

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

知道上一题为啥会少一些情况了....
字典序小的排列被略去了， 所以开始的时候还是要排序一下。

class Solution {
public:
    vector<vector<int>> permuteUnique(vector<int>& nums) {
        sort(nums.begin(), nums.end());
        vector<vector<int>> ans;
        do{
            ans.push_back(nums);
        }while(next_permutation(nums.begin(), nums.end()));
        return ans;
    }
};