LeetCode 59. Spiral Matrix II

https://leetcode.com/problems/spiral-matrix-ii/

#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>
#include <vector>
#include <map>
#include <iostream>

using namespace std;

class Solution {
public:
    vector< vector<int> > generateMatrix(int n) {
        int mtx[n][n];
        int left=0,right=n,up=0,down=n;
        int cnt=1;
        while(cnt <= n*n) {
            for(int i=left; i<right; i++)
                mtx[up][i] = cnt, cnt++;
            if(cnt > n*n)break;
            for(int i=up+1; i<down; i++)
                mtx[i][right-1] = cnt, cnt++;
            if(cnt > n*n)break;
            for(int i=right-2;i>=left;i--)
                mtx[down-1][i] = cnt, cnt++;
            if(cnt > n*n) break;
            for(int i=down-2; i>up; i--)
                mtx[i][left] = cnt , cnt ++;
            left++,up++;
            down--,right--;
        }
        vector < vector<int> >ret;
        for(int i=0;i<n;i++) {
            vector <int> iv;
            for(int j=0;j<n;j++)
                iv.push_back(mtx[i][j]);//, cout << mtx[i][j] << "*, ";
            ret.push_back(iv);
        }
        return ret;

    }
};

int main() {
    int n;
    while(cin >> n) {
        Solution s;
        vector <  vector<int> > ivec = s.generateMatrix(n);
        for(int i=0;i<ivec.size();i++) {
            for(int j=0;j<ivec[0].size();j++)
                cout << ivec[i][j] << ",";
            cout << endl;
        }

    }
    return 0;

}