POJ1979 Red and Black
Red and Black
| Time Limit: 1000MS | Memory Limit: 30000K | |
| Total Submissions: 28659 | Accepted: 15614 |
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
Source
Japan 2004 Domestic
简单的DFS，练练手，直接代码吧。
Source Code
Problem: 1979 User: lk951208
Memory: 252K Time: 0MS
Language: C++ Result: Accepted
Source Code
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define MAXN 300
using namespace std;
char mp[MAXN][MAXN];
int N,M,ans;
void dfs(int r,int c)
{
if(r<0 || r>=M || c<0 || c>=N) return;
if(mp[r][c]=='#') return;
if(mp[r][c]!='#') {ans++;mp[r][c]='#';}
dfs(r+1,c);
dfs(r-1,c);
dfs(r,c+1);
dfs(r,c-1);
}
int main()
{
while(scanf("%d%d",&N,&M) && N && M)
{
int x,y;ans=0;
memset(mp,0,sizeof(mp));
for(int i=0;i<M;i++)
{
scanf("%s",mp[i]);
for(int j=0;j<N;j++)
if(mp[i][j]=='@') {x=i;y=j;}
}
dfs(x,y);
printf("%d\n",ans);
}
return 0;
}