一个C语言难题 高手来~red and black

//以下代码在我的机器上调试通过 vs2005 我估计在vc6.0也行
//因为我是用纯C来写的
//请注意放一个input.txt里面写上数据
//这个算法采用DFS递归方式来寻找的.
//算法在一秒内就运行完成了

//
/*
18. Red and Black
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
45
59
6
13

*/

#include
#define maxsize 20
unsigned char room[maxsize][maxsize];
unsigned int counter = 0;
unsigned int W = 0;
unsigned int H = 0;

void Find(unsigned int i,unsigned int j)
{
counter++;
if(j>0 && (room[i][j-1] == '.'))
{
room[i][j-1] = '#';
Find(i,j-1);
}

if(i>0 && (room[i-1][j] == '.'))
{
room[i-1][j] = '#';
Find(i-1,j);
}

if((j+1){
room[i][j+1] = '#';
Find(i,j+1);
}

if((i+1){
room[i+1][j] = '#';
Find(i+1,j);
}
}

int main()
{
unsigned int i,j,si,sj;
char c;
FILE *f;
if(NULL == (f = fopen("input.txt","r")))
{
printf("Can't open input.txt\n");
return -1;
}
fscanf(f,"%d%d",&W,&H);
for(i=0;i {
for(j=0;j {
c = getc(f);
if(c=='.'||c=='#'||c=='@')
{
if('@' == c)
{si = i; sj = j;}
room[i][j] = c;
j++;
}
}
}
fclose(f);
Find(si,sj);
printf("counter=%d\n",counter);
getchar();
return 0;
}

回去看看C语言数据结构里面的迷宫游戏！

干吗写英语?

额~难道是竞赛题?