Red and Black（深搜

Red and Black

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 26031    Accepted Submission(s): 15730

 

Problem Description

There is a rectangular room, covered with square tiles. Each tile is colored either red or black. A man is standing on a black tile. From a tile, he can move to one of four adjacent tiles. But he can't move on red tiles, he can move only on black tiles.

Write a program to count the number of black tiles which he can reach by repeating the moves described above. 

 

 

Input

The input consists of multiple data sets. A data set starts with a line containing two positive integers W and H; W and H are the numbers of tiles in the x- and y- directions, respectively. W and H are not more than 20.

There are H more lines in the data set, each of which includes W characters. Each character represents the color of a tile as follows.

'.' - a black tile 
'#' - a red tile 
'@' - a man on a black tile(appears exactly once in a data set) 

 

 

Output

For each data set, your program should output a line which contains the number of tiles he can reach from the initial tile (including itself). 

 

 

Sample Input

6 9 ....#. .....# ...... ...... ...... ...... ...... #@...# .#..#. 11 9 .#......... .#.#######. .#.#.....#. .#.#.###.#. .#.#..@#.#. .#.#####.#. .#.......#. .#########. ........... 11 6 ..#..#..#.. ..#..#..#.. ..#..#..### ..#..#..#@. ..#..#..#.. ..#..#..#.. 7 7 ..#.#.. ..#.#.. ###.### ...@... ###.### ..#.#.. ..#.#.. 0 0

 

 

Sample Output

45 59 6 13

真的要细心呐，这么简单的题，debug半天。在不细心就凉透了。

AC代码：

#include
#include
char map[21][21];
int vis[21][21];
int m,n,sx,sy,sum;
int next[4][2]={0,-1,0,1,1,0,-1,0};
void dfs(int sx,int sy)
{
	int fx,fy;
	vis[sx][sy]=1;
	sum++;
	for(int i=0;i<4;i++)
	{
		fx=sx+next[i][1],fy=sy+next[i][0];
		if(fx<0||fy<0||fx>=n||fy>=m||vis[fx][fy]==1||map[fx][fy]=='#') continue;
		dfs(fx,fy);
	}
}

int main()
{
	while(~scanf("%d%d",&m,&n)&&m&&n)
	{
		for(int i=0;i