参考答案：

#include<iostream>
#include<algorithm>
using namespace std;
const int N = 1010;
char a[N][N];
int main()
{
    int n;
    cin >> n;
    for (int i = 1; i <= n; ++i)
    {
        for (int j = 1; j <= n; ++j)
        {
            cin >> a[i][j];
        }
    }
    int m = n;
    int k = 1;
    while (m)
    {
        int t = n;
        while (t)
        {
            cout << a[t][k];
            --t;
        }
        cout << '\n';
        ++k;
        --m;
    }
    return 0;
}