# leetcode 47. Permutations II

## Permutation

class Solution {
public:
    void recur(vector<int> nums, vector<int> ans, vector<vector<int>>& res, int size){
        if(!size){
            res.push_back(ans);
            return;
        }
        
        for(int i = 0; i < size; i++){
            if(i > 0 && nums[i] == nums[i - 1]) continue;
            ans.push_back(nums[i]);
            vector<int> temp = nums;
            temp.erase(temp.begin() + i);
            recur(temp, ans, res, size - 1);
            ans.pop_back();
        }
        
    }
    vector<vector<int>> permuteUnique(vector<int>& nums) {
        sort(nums.begin(), nums.end());
        vector<vector<int>> res;
        vector<int> ans;
        recur(nums, ans, res, nums.size());
        return res;
    }
};

## swap

class Solution {
public:
    void recur(vector<int> nums, vector<vector<int>>& res, int j, int size){
        if(j == size){
            res.push_back(nums);
            return;
        }
        
        for(int i = j; i < size; i++){
            if(i != j && nums[i] == nums[j]) continue;
            swap(nums[i], nums[j]);
            recur(nums, res, j + 1, size);
        }
        
    }
    vector<vector<int>> permuteUnique(vector<int>& nums) {
        sort(nums.begin(), nums.end());
        vector<vector<int>> res;
        recur(nums, res, 0, nums.size());
        return res;
    }
};

###### tags: `leetcode` `c++`