HDU 1312Red and Black

Red and Black

Time Limit:1000MS     Memory Limit:32768KB     64bit IO Format:%I64d & %I64u

Submit Status Practice HDU 1312

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

4559613

</pre><p></p><p><pre name="code" class="cpp">#include<stdio.h>#include<string.h>int vis[1010][1010];char map[1010][1010];int sx,sy,ans,m,n;void dfs(int x,int y){if(x<0||x>=m||y<0||y>=n||vis[x][y]||map[x][y]=='#')return;vis[x][y]=1;ans++;dfs(x,y+1);dfs(x+1,y);dfs(x,y-1);dfs(x-1,y);}int main(){while(~scanf("%d%d",&n,&m)&&m!=0&&n!=0){memset(vis,0,sizeof(vis));memset(map,0,sizeof(map));ans=0;for(int i=0;i<m;i++){scanf("%s",&map[i]);for(int j=0;j<n;j++)if(map[i][j]=='@')sx=i,sy=j;}dfs(sx,sy);printf("%d\n",ans);}return 0;}