蛇形填数

<span style="font-size:18px;">#include <stdio.h>#include <stdlib.h>#include <string.h>#define MAXN 50int a[MAXN][MAXN];int main(){    int n;    int x,y;    int total;    while(~scanf("%d",&n))    {        total = 0;        x = 0; y = n-1;        memset(a,0,sizeof(a));        total = a[x][y] = 1;        while(total<n*n)        {            while(x<n-1 && !a[x+1][y]) a[++x][y] = ++total;            while(y>0 && !a[x][y-1]) a[x][--y] = ++total;            while(x>0 && !a[x-1][y]) a[--x][y] = ++total;            while(y<n-1 && !a[x][y+1]) a[x][++y] = ++total;        }        for(x=0; x<n; x++)        {            for(y=0; y<n; y++)            {                printf("%4d ",a[x][y]);            }            putchar('\n');        }    }    return 0;}</span>