Red and Black
| Time Limit: 1000MS | Memory Limit: 30000K | |
| Total Submissions: 31722 | Accepted: 17298 |
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
Source
#include "cstdio"
#include "cstring"
#include "cmath"
#include "iostream"
#include "string" using namespace std ;
const int maxN = ; const int dx[ ] = { , , , - } ;
const int dy[ ] = { , , - , } ; char mp[ maxN ][ maxN ] ;
int N , M ; void DFS ( const int xi , const int yi ) {
if ( !mp[ xi ][ yi ] )return ;
mp[ xi ][ yi ] = '%' ;
for ( int i= ; i< ; ++i ) {
int xx = xi + dx[ i ] ;
int yy = yi + dy[ i ] ;
if ( xx > && xx <= M && yy > && yy <= N && mp[ xx ][ yy ] == '.' )
DFS( xx , yy ) ;
}
} int sumerize ( const int n , const int m ) {
int ret ( ) ;
for ( int i= ; i<=n ; ++i ) {
for ( int j= ; j<=m ; ++j ) {
if ( mp[ i ][ j ] == '%' ) ++ret ;
}
}
return ret ;
} int main ( ) {
int start_x , start_y ;
while ( scanf ( "%d%d\n" , &N , &M ) == && N && M ) {
for ( int i= ; i<=M ; ++i ) {
scanf ( "%s" , mp[ i ] + ) ;
}
for ( int i= ; i<=M ; ++i ) {
for ( int j= ; j<=N+ ; ++j ) {
if ( mp[ i ][ j ] == '@' ) {
mp[ i ][ j ] = '.' ;
start_x = i ;
start_y = j ;
goto Loop ;
}
}
}
Loop :
DFS ( start_x , start_y ) ; printf ( "%d\n" , sumerize ( M , N ) ) ;
memset ( mp , , sizeof ( mp ) ) ;
} return ;
}
2016-10-21 16:28:48