permutation swap으로 세기

gistfile1.txt

void permutation(vector<vector<int>>& res, vector<int> input, int startIndex) {
    if(input.size() <= startIndex) {
        res.push_back(input);
    } else {
        for(int i=startIndex ; i<input.size() ; i++) {
            vector<int>temp = input;
            
            int tempElement = temp[i]; //swap
            temp[i] = temp[startIndex];
            temp[startIndex] = tempElement;
            
            permutation(res, temp, startIndex+1);
        }
    }
}

int main()
{
   vector<vector<int>> res;
   vector<int> input = {1,2,3,4};
   
   permutation(res, input, 0);
   
   for(int i=0; i<res.size(); i++) {
        for(int j=0; j<res[i].size(); j++) {
            cout<<res[i][j]<<"  ";   
        }
        cout<<endl;
   }
   
   return 0;
}