蛇形矩阵

#include<stdio.h>

#include<string.h>

const int maxn = 12;//the size of the maze

int a[ maxn ][ maxn ];

const int dx[]={0,1,0,-1};

const int dy[]={1,0,-1,0};

bool inside( int x,int y,int n ){

	if( x>=0&&x<n&&y>=0&&y<n ) return true;

	else return false;

}

int main(){

	int ca;

	scanf("%d",&ca);

	for( int t=0;t<ca;t++ ){

		int n;

		scanf("%d",&n);

		printf("case #%d:\n",t);

		memset( a,0,sizeof( a ) );

		/*

		for( int i=0;i<=n;i++ ){

			a[ i ][ n ] = -1;

			a[ n ][ i ] = -1;

		}

		*/

		int cnt = 1;

		int pos = 0;

		int x,y;

		x = y = 0;

		int tx,ty;

		tx=ty=0;

		while( cnt<=n*n ){

			if( inside( tx,ty,n )==true&&a[ tx ][ ty ]==0 ){

				a[ tx ][ ty ] = cnt++;

				x=tx,y=ty;

			}

			else{

				pos++;

				pos%=4;

			}

			tx=x+dx[pos],ty=y+dy[pos];

			//x += dx[ pos ],y += dy[ pos ];

		}



		for( int i=0;i<n;i++ ){

			for( int j=0;j<n;j++ ){

				if( j==0 ) printf("%d",a[i][j]);

				else printf(" %d",a[i][j]);

			}

			printf("\n");

		}

	}

	return 0;

}