Red and Black
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 10286 Accepted Submission(s): 6426
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 .#......... .#.#######. .#.#.....#. .#.#.###.#. .#.#[email protected]#.#. .#.#####.#. .#.......#. .#########. ........... 11 6 ..#..#..#.. ..#..#..#.. ..#..#..### ..#..#..#@. ..#..#..#.. ..#..#..#.. 7 7 ..#.#.. ..#.#.. ###.### [email protected] ###.### ..#.#.. ..#.#.. 0 0
Sample Output
45 59 6 13
Source
Asia 2004, Ehime (Japan), Japan Domestic
做好细节工作，迫在眉睫！！！本来测试数据三组都对了，最后一组怎么都不对，调试了一中午，才发现是map数组忘了初始化了。。。。
代码如下：
#include<stdio.h>
#include<string.h>
char map[1001][1001];
int visit[1001][1001];
int count,n,m;
void dfs(int a,int b)
{
if(a<0||b<0||a>=1001||b>=1001)
return ;
if(!visit[a-1][b]&&map[a-1][b]=='.')
{
visit[a-1][b]=1;
count++;
dfs(a-1,b);
// visit[n-1][m]=0;
}
if(!visit[a][b-1]&&map[a][b-1]=='.')
{
visit[a][b-1]=1;
count++;
dfs(a,b-1);
// visit[n][m-1]=0;
}
if(!visit[a+1][b]&&map[a+1][b]=='.')
{
visit[a+1][b]=1;
count++;
dfs(a+1,b);
// visit[n+1][m]=0;
}
if(!visit[a][b+1]&&map[a][b+1]=='.')
{
visit[a][b+1]=1;
count++;
dfs(a,b+1);
// visit[n][m+1]=0;
}
else
return ;
}
int main()
{
int i,j;
while(~scanf("%d%d",&n,&m),n||m)
{
count=1;
memset(visit,0,sizeof(visit));
memset(map,'#',sizeof(map));//这个一定要加上，就因为这个疏忽，我足足调试了一中午。。。
for(i=0;i<m;++i)
{
scanf("%s",map[i]);
}
for(i=0;i<m;++i)
{
for(j=0;j<n;++j)
{
if(map[i][j]=='@')
{
dfs(i,j);
printf("%d\n",count);
break;
}
}
}
}
return 0;
}