CodeForce 710C Magic Odd Square

Magic Odd Square

　　Find an n × n matrix with different numbers from 1 to n², so the sum in each row, column and both main diagonals are odd.

Input

　　The only line contains odd integer n (1 ≤ n ≤ 49).

Output

　　Print n lines with n integers. All the integers should be different and from 1 to n². The sum in each row, column and both main diagonals should be odd.

Examples

 

Input

 

1

Output

 

1

Input

 

3

Output

 

2 1 4
3 5 7
6 9 8
题意：
　　就是给一个奇数n，使n * n 的方格，行，列，主对角线相加为奇数。输出这样的正方形
思路：
　　先在第一行中间放上1，然后向右上放数，有数了就放在当前的正下方，一直到结束。

AC代码：

# include <bits/stdc++.h>
using namespace std;
const int MAX = 50;
int a[MAX][MAX];
bool vis[MAX][MAX];
int main()
{
    int n;
    scanf("%d", &n);
    memset(vis, false, sizeof(vis));
    a[1][n/2 + 1] = 1;
    int r = 1;
    int c = n/2 + 1;
    vis[r][c] = true;
    for(int i = 2; i <= n * n; i++)
    {
        int r1 = r;
        int c1 = c;
        r -= 1;
        c += 1;
        if(r < 1)
            r = n;
        if(c > n)
            c = 1;
        if(vis[r][c])
        {
            r = r1 + 1;
            c = c1;
        }
        vis[r][c] = true;
        a[r][c] = i;
        
    }
    for(int i = 1; i <= n; i++)
    {
        for(int j = 1; j <= n; j++)
        {
            if(j == 1)
                cout << a[i][j];
            else
                cout << " " << a[i][j];
        }
        cout << endl;
    }
    return 0;
}