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
45
59
6
13
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 ;
}