dfs Red and Black
Description
Input
Output
Sample Input
Sample Output
Hint
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)
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 .#......... .#.#######. .#.#.....#. .#.#.###.#. .#.#..@#.#. .#.#####.#. .#.......#. .#########. ........... 11 6 ..#..#..#.. ..#..#..#.. ..#..#..### ..#..#..#@. ..#..#..#.. ..#..#..#.. 7 7 ..#.#.. ..#.#.. ###.### ...@... ###.### ..#.#.. ..#.#.. 0 0
Sample Output
45 59 6 13
#include<stdio.h>
#include<string.h>
#include<math.h>
#include<stdlib.h>
#include<algorithm>
#include<iostream>
#include<queue>
using namespace std;
int n, m;
int chess[25][25];
bool visited[25][25];
int d[4][2] = { 0,1,1,0,-1,0,0,-1 };
int sum = 0;
void dfs(int x,int y)
{
int tx, ty;
for(int i=0;i<4;i++)
{
tx = x + d[i][0];
ty = y + d[i][1];
if (tx < 0 || tx >= n || ty<0 || ty>=m || chess[ty][tx]=='#' || visited [ty][tx]==true)
{
continue;
}
visited[ty][tx] = true;
sum += 1;
dfs(tx, ty);
}
}
int main()
{
while(~scanf("%d %d",&n,&m))
{
sum = 0;
memset(visited, false, sizeof(visited));
int x, y;
if (n == 0 && m == 0) { break; }
getchar();
for(int i=0;i<m;i++)
{
for(int j=0;j<n;j++)
{
scanf("%c", &chess[i][j]);
if(chess[i][j]=='@')
{
x = j;
y = i;
}
}
getchar();
}
visited[y][x] = true;
sum+=1;
dfs(x, y);
printf("%d\n", sum);
}
return 0;
}//by tp
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