蛇形打印

#include<cstdio>
#include<cstring>
const int N = 10;
int a[N][N];
int main(){
    int n,x,y,tot;    
    memset(a,0,sizeof(a));
    scanf("%d",&n);//n行n列 

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