题解 | #回型矩阵#

#include <stdio.h>

int main()
{
    int n = 0;
    scanf("%d",&n);
    int arr[20][20] = {0};
    int i = 0;
    int j = 0;
    int up = 0;
    int down = n-1;
    int right = n-1;
    int left = 0;
    int x = 1;
    while(x<=n*n)
    {
        for(i = left;i<=right;i++)
        {
            arr[up][i] = x++;
        }
        up++;
        for(i = up;i<=down;i++)
        {
            arr[i][right] = x++;
        }
        right--;
        for(i = right;i>=left;i--)
        {
            arr[down][i] = x++;
        }
        down--;
        for(i = down;i>=up;i--)
        {
            arr[i][left] = x++;
        }
        left++; 
    }
    for(i = 0;i<n;i++)
    {
        for(j = 0;j<n;j++)
        {
            
            printf("%d ",arr[i][j]);
        }
        printf("\n"); 
    }
    return 0;
}