杭电Red and Black。。。。水题

Red and Black

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 14279    Accepted Submission(s): 8852

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

4559613
 
 
 
#include <iostream>using namespace std;char a[22][22];   int m,n;int p,q;int cnt;void dfs (int x, int y)  {      if (a[x][y]=='#' || x < 1 || x >n|| y < 1 || y > m)          return ;      ++cnt ;      a[x][y] ='#';  dfs (x-1, y) ;      dfs (x, y-1) ;      dfs (x+1, y) ;      dfs (x, y+1) ;  }  int main (){while(cin>>m>>n){int i,j;if(m==0&&n==0) break;for( i=1;i<=n;i++)for( j=1;j<=m;j++){cin>>a[i][j];if(a[i][j]=='@'){p=i;q=j;                    a[i][j] = '.' ;  }}cnt=0;dfs(p,q);cout<<cnt<<endl;}return 0;}