LeetCode 46. Permutations

distinct

For example,

[1,2,3] have the following permutations:

[ [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], [3,2,1] ]

answer:

class Solution {
public:
    vector<vector<int>> permute(vector<int>& nums) {
        int length = nums.size();
        vector<vector<int>> result1,result2;
        vector<int> temp;
        result1.push_back(temp);
        bool flag = false;
        for(int i = 0; i < length; i ++){
            for(int k = 0;k < length; k ++){
                for(int j = 0; j < result1.size(); j ++){
                    flag = false;
                    temp = result1[j];
                    for(int l = 0; l < temp.size(); l ++){
                        if(temp[l] == nums[k]){
                            flag = true;
                            break;
                        }
                    }
                    if(flag) continue;
                    temp.push_back(nums[k]);
                    result2.push_back(temp);
                    temp.pop_back();
                }
            }
            result1 = result2;
            result2.clear();
        }
        return result1;
    }
    
};