蛇形填数

#include<stdio.h>#include<string.h>#define N 20int a[N][N];int main(){    int n,i,j;    while(scanf("%d",&n)!=EOF)    {         int x,y,count=1;         memset(a,0,sizeof(a));         a[x=0][y=n-1]=1;            while(count<n*n)         {               while(x+1<n&&!a[x+1][y])    a[++x][y]=++count;               while(y-1>=0&&!a[x][y-1])    a[x][--y]=++count;               while(x-1>=0&&!a[x-1][y])    a[--x][y]=++count;               while(y+1<n&&!a[x][y+1])    a[x][++y]=++count;     //x y为走的坐标位置          }       for(i=0;i<n;i++)       {          for(j=0;j<n;j++)            printf("%3d",a[i][j]);            printf("\n");       }        }    return 0;}