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.
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> #include<iostream> using namespace std; int n,m,dir[4][2]={{1,0},{-1,0},{0,1},{0,-1}},sum; char map[25][25]; int DFS(int i,int j) { int e; map[i][j]='#'; sum++; for(e=0;e<4;e++) if(i+dir[e][0]>=0&&i+dir[e][0]<n&&j+dir[e][1]>=0&&j+dir[e][1]<m) if(map[i+dir[e][0]][j+dir[e][1]]!='#') DFS(i+dir[e][0],j+dir[e][1]); } int main() { int i,j,pi,pj; while(scanf("%d%d",&m,&n)>0&&(m||n)) { for(i=0;i<n;i++) { getchar(); for(j=0;j<m;j++) { scanf("%c",&map[i][j]); if(map[i][j]=='@') { pi=i;pj=j; } } } sum=0; DFS(pi,pj); printf("%d\n",sum); } }