本题解用了二维数组和for循环

思路：按列填充，第 c 列第 r 行数字 = c * N + r + 1

#include <iostream>
using namespace std;

int main()
{
    int N;
    cin >> N;
    int mat[10][10] = {0};

    int num = 1;
    for (int c = 0; c < N; c++)
    {
        for (int r = 0; r < N; r++)
        {
            mat[r][c] = num++;
        }
    }
    for (int r = 0; r < N; r++)
    {
        for (int c = 0; c < N; c++)
        {
            if (c > 0) cout << " ";
            cout << mat[r][c];
        }
        cout << endl;
    }

    return 0;
}