Red and Black
Time Limit: 1000MS | Memory Limit: 30000K | |
Total Submissions: 26216 | Accepted: 14238 |
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.
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.
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
题意:给你一个装‘#’,‘@’,‘.’的二维数组,从‘@’出发,‘.’代表可以走,‘#’代表不能走。求最多能走多少步;
思路:直接DFS吧,朝四个不同的方向走;
代码如下:
#include < cstdio >//为什么我的头文件发表出来就看不到了?
#include < cstring >
char s[25][25];
int m,n;
int i,j,ans;
int dfs(int i,int j)
{
if(i<0||j<0||i>=n||j>=m)//可不能出界额;
return 0;
if(s[i][j]!='#')
{
s[i][j]='#';//走过的路,标记一下,下次不能再走;
return 1+dfs(i+1,j)+dfs(i-1,j)+dfs(i,j+1)+dfs(i,j-1);//四个不同的方向;
}
else
return 0;//保证走不通时就结束;
}
int main()
{
while(~scanf("%d%d",&m,&n))
{
if(m==0&&n==0)
break;
for(i=0;i < n;i++)
scanf("%s",&s[i]);
for(i=0;i < n;i++)
for(j=0;j < m;j++)
{
if(s[i][j]=='@')
ans=dfs(i,j);
}
printf("%d\n",ans);
}
return 0;
}