蛇形填数

#include<stdio.h>#include<string.h>#define MAXN 10int 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;}