Red and Black

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 19690 Accepted Submission(s): 11965

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

Sample Output

代码:

 #include<bits/stdc++.h>

 using namespace std;

 int direct [][]={-,,,,,,,-};

 char str[][];

 bool flag[][];

 int w,h,ans;

 void DFS(int x,int y){

     for(int i=;i<;i++){

         int p=x+direct[i][];

         int q=y+direct[i][];

         if(p>=&&p<h&&q>=&&q<w&&flag[p][q]==&&str[p][q]=='.'){

             ans++;

             flag[p][q]=;

             DFS(p,q);

         }

     }

 }

 int main(){

     int Dx,Dy;

     while(~scanf("%d%d",&w,&h)){

         if(w==&&h==)break;

         memset(flag,,sizeof(flag));

         getchar();

         for(int i=;i<h;i++){

             for(int j=;j<w;j++){

                 scanf("%c",&str[i][j]);

                 if(str[i][j]=='@'){

                     Dx=i;

                     Dy=j;

                 }

             }getchar();

         }

         ans=;

         flag[Dx][Dy]=;

         DFS(Dx,Dy);

         printf("%d\n",ans);

     }

     return ;

 }

巴特西

HDU1312-Red and Black-DFS

Red and Black

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