Red and Black ---路线问题

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

 

 

 

 

#include <stdio.h> #define N 22 char ch[N][N]; int m ,n; int fin(int x, int y) { if(x<0 || x>=n || y<0 || y>=m) return 0; else if(ch[x][y]=='#') return 0; else { ch[x][y] = '#'; return 1+fin(x-1, y)+fin(x+1, y)+fin(x, y-1)+fin(x, y+1); } } int main() { int i, j; int x, y, a; while (scanf("%d%d", &m, &n), m!=0 && n!=0) { for(i = 0; i<n; i++) { for (j =0; j<m; j++) { scanf(" %c", &ch[i][j]); if (ch[i][j]=='@') { x = i; y = j; } } } a = fin(x, y); printf("%d\n", a); } return 0; }