蛇形填数

#include<stdio.h>
#include<string.h>
#define MAXN 10
int a[MAXN][MAXN];

int main()

{
    int n,x,y,tot = 0;
    scanf("%d",&n);
    memset(a,0,sizeof(a));
    tot = a[x = 0][y = n - 1] = 1;
    while(tot < n*n)
    {
        while(x + 1 < n&&!a[x + 1][y])a[++x][y] = ++tot;
        while(y - 1 >= 0&& !a[x][y-1])a[x][--y] = ++tot;
        while(x - 1 >= 0&& !a[x-1][y])a[--x][y] = ++tot;
        while(y+1 < n&&!a[x][y+1])a[x][++y] = ++tot;
    }
    for(x = 0; x < n;x++)
    {
        for(y = 0;y < n;y++)printf("%3d",a[x][y]);
        printf("\n");
    }
    return 0;
}