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]
]

解决代码：

class Solution {
public:
vector<vector<int>> permuteUnique(vector<int>& nums) {
vector<vector<int>> res;//结果
sort(nums.begin(), nums.end());
vector<int> resm;//单个结果
int len = nums.size();
permute(nums, res, resm, len);
return res;
}
private:
void permute(vector<int> nums, vector<vector<int>>& res, vector<int>& resm, int len){
if(resm.size() == len)
{
res.push_back(resm);
}
else
{
for(int i = 0; i < nums.size(); i++)
{
if(i && nums[i]==nums[i-1])
continue;
resm.push_back(nums[i]);
vector<int> temp = nums;
temp.erase(temp.begin()+i);
permute(temp, res, resm, len);
resm.pop_back();
}
}

}
};