HD1312 Red and Black【递归】

Red and Black

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 13136    Accepted Submission(s): 8136

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

4559613

 

题意：@周围走过来，总共能走多少个‘.’，‘#’不能走。

AC代码

#include<stdio.h>#include<string.h>char a[25][25];int count,m,n;void fun(int x,int y){if(a[x][y]=='#')return ;if(x<1||y>m||x>n||y<1)return ;count++;a[x][y]='#';//走过的路标记为#。 //count++;fun(x-1,y);  fun(x+1,y);fun(x,y-1);fun(x,y+1);}int main(){int b,c,i,j;while(scanf("%d %d",&m,&n)&&(m!=0||n!=0)){ count=0;for(i=1;i<=n;i++){getchar();for(j=1;j<=m;j++){scanf("%c",&a[i][j]);if(a[i][j]=='@'){c=i,b=j;}}    }    fun(c,b);    printf("%d\n",count);    }}