A - Red and Black(3.2.1)（搜索）

A - Red and Black(3.2.1)

Time Limit:1000MS     Memory Limit:30000KB     64bit IO Format:%I64d & %I64u

Submit Status

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) 
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

4559613

#include<iostream>#include<cstring>using namespace std;int b,c,k,i,s,x,y,n;char a[21][21]; int sousuo(int x,int y,int a1,int b){int n=0;if(x>0)if(a[x-1][y]=='.'){n++;a[x-1][y]='a';n=n+sousuo(x-1,y,a1,b);}    if(y>0)if(a[x][y-1]=='.'){n++;a[x][y-1]='a';n=n+sousuo(x,y-1,a1,b);}if(x<a1)      if(a[x+1][y]=='.'){n++;a[x+1][y]='a';n=n+sousuo(x+1,y,a1,b);}  if(y<b)if(a[x][y+1]=='.'){n++;a[x][y+1]='a';n=n+sousuo(x,y+1,a1,b);}return n;}int main(){int j;while(cin>>k>>s&&k){memset(a,'q',sizeof(a));  for(i=0;i<s;i++)  for(j=0;j<k;j++)  {  cin>>a[i][j];  if(a[i][j]=='@')  x=i,y=j;  }         n=sousuo(x,y,s,k); cout<<++n<<endl;}return 0;}