Red and Black

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. InputThe 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) OutputFor 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<stdio.h>  #include<string.h>  #include<algorithm>  #define INF 0x3f3f3f3f  #define M 300  using namespace std;  int dx[4]={0,1,-1,0};  int dy[4]={1,0,0,-1};  int n,m,x,y;   bool vis[M][M];  char map[M][M];  int ans;  void F(int xx,int yy)  {      int i,j;      for(i=0;i<4;i++)      {          if(map[xx+dx[i]][yy+dy[i]]=='.'&&vis[xx+dx[i]][yy+dy[i]]==false&&xx+dx[i]>=0&&yy+dy[i]>=0&&xx+dx[i]<m&&yy+dy[i]<n)          {              vis[xx+dx[i]][yy+dy[i]]=true;  //做标记             ans++;              F(xx+dx[i],yy+dy[i]); //知道全部访问完         }      }  }  int main()  {      while(scanf("%d%d",&n,&m)&&(n||m))      {             memset(vis,false,sizeof(vis));          for(int i=0;i<m;i++)          {              getchar();//输入字符串              for(int j=0;j<n;j++)              {                  scanf("%c",&map[i][j]);                  if(map[i][j]=='@')                  {                      x=i,y=j; // 记录下@的位置                     vis[i][j]=true; //标记@的位置                 }              }          }          ans=0;          F(x,y);          printf("%d\n",ans+1);      }      return 0;  } 

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 adj995eacent tiles. But he can't move on red tiles, he can moveonly on black tiles. Write a program to count the number of black tiles which he can reach by repeating the moves described above. InputThe 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) OutputFor 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