题目要求：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], and [2,1,1].
代码如下：
class Solution { public: vector<vector<int> > permuteUnique(vector<int> &num) { vector<vector<int>> result; sort(num.begin(), num.end()); do{ result.push_back(num); }while(next_permutation(num.begin(), num.end())); return result; } };
原文：http://www.cnblogs.com/510602159-Yano/p/4279318.html