HDU 1312 Red and Black (DFS)

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

6 9

....#.

.....#

......

......

......

......

......

#@...#

.#..#.

11 9

.#.........

.#.#######.

.#.#.....#.

.#.#.###.#.

.#.#..@#.#.

.#.#####.#.

.#.......#.

.#########.

...........

11 6

..#..#..#..

..#..#..#..

..#..#..###

..#..#..#@.

..#..#..#..

..#..#..#..

7 7

..#.#..
..#.#..

###.###

...@...

###.###

..#.#..

..#.#..

0 0

 

Sample Output

45

59

6

13

要小心它的输入

行列是相反的

坑在这里找了好多次TAT

 #include<stdio.h>
 #include<iostream>
 using namespace std;
 char map[][];
 int n,m;
 int num;
 int rx[]={,,,-};
 int ry[]={,-,,};
 void dfs(int i,int j)
 {
     map[i][j]='#';
     num++;
     int t,x,y;
     for(t=;t<;t++)
     {
         x=i+rx[t];
         y=j+ry[t];
         if(x>= && x<n && y>= && y<m && map[x][y]=='.')
             dfs(x,y);
     }
 }
 int main()
 {
     int i,j;
     int si,sj;
     while(scanf("%d%d",&m,&n)!=EOF)//原来是行数和列数反了...我真是醉了....
     {

         if(m==&&n==)break;
         for(i=;i<n;i++)
             for(j=;j<m;j++)
             {
                 cin>>map[i][j];
                 if(map[i][j]=='@')
                 {
                     si=i;
                     sj=j;
                 }
             }
         num=;
         dfs(si,sj);
         printf("%d\n",num);
     }
     return ;
 }