参考答案：

#include<iostream>
using namespace std;
const int N = 1010;
int n;
int a[N][N];
int main() 
{
    cin >> n;
    int i = 1, j = 1;
    bool flag = 1;
    for (int cnt = 1; cnt <= (n * n + 1) / 2; cnt++) 
    {
        a[i][j] = cnt;
        if (flag == 1) 
        {
            if (i == 1) 
            {
                j++;
                flag = 0;
            }
            else 
            {
                i--;
                j++;
            }
        }
        else 
        {
            if (j == 1) 
            {
                i++;
                flag = 1;
            }
            else 
            {
                i++;
                j--;
            }
        }
    }
    for (int i = 1; i <= n; i++) 
    {
        for (int j = 1; j <= n; j++) 
        {
            if (a[i][j] == 0) 
            {
                a[i][j] = n * n + 1 - a[n - i + 1][n - j + 1];
            }
            cout << a[i][j] << " ";
        }
        cout << endl;
    }
}