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)
The end of the input is indicated by a line consisting of two zeros.
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
dfs
#include<iostream>
#include<string.h>
#include<stdio.h>
using namespace std;
char map[105][105];
int star_x,star_y;
int a[4]={1,-1,0,0};
int b[4]={0,0,1,-1};
int n,m;
int sum=1;
int judge(int x,int y)
{
if(x>=0&&x<m&&y>=0&&y<n&&map[x][y]=='.'&&map[x][y]!='#')
return 1;
else
return 0;
}
int dfs(int star_x,int star_y)
{
int dx,dy;
for(int i=0;i<4;i++)
{
dx=star_x+a[i];
dy=star_y+b[i];
if(judge(dx,dy))
{
sum++;
map[dx][dy]='#';
dfs(dx,dy);
//map[dx][dy]='#';
// sum++;
}
}
}
int main()
{
//int n,m;
while(scanf("%d%d",&n,&m))
{
// memset(map,0,sizeof(map));
if(n<=0||m<=0)break;
sum=1;
for(int i=0;i<m;i++)
{
for(int j=0;j<n;j++)
{
cin>>map[i][j];
if(map[i][j]=='@')
{
star_x=i;
star_y=j;
}
}
}
// map[star_x][star_y]='.';
dfs(star_x,star_y);
cout<<sum<<endl;
}
return 0;
}