题意 求矩阵中包含‘@’的‘.‘连通块中元素数量 ‘@‘也看做‘.‘
最基础的dfs了
#include<cstdio>
#include<cstring>
using namespace std;
const int N = 30;
char mat[N][N];
int dx[4] = {0, 0, -1, 1}, dy[4] = { -1, 1, 0, 0};
int ans;
void dfs(int r, int c)
{
if(mat[r][c] != '.') return;
mat[r][c] = '#';
for(int i = 0; i < 4; ++i)
{
int x = r + dx[i], y = c + dy[i];
if(mat[x][y] == '.')
{
dfs(x, y);
++ans;
}
}
}
int main()
{
int m, n, sx, sy;
while(scanf("%d%d", &m, &n), m)
{
memset(mat, 0, sizeof(mat));
for(int i = 1; i <= n; ++i)
scanf("%s", mat[i] + 1);
for(int i = 1; i <= n; ++i)
for(int j = 1; j <= m; ++j)
if(mat[i][j] == '@') sx = i, sy = j;
ans = 1;
dfs(sx, sy);
printf("%d\n", ans);
}
}
Red and Black
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 .#......... .#.#######. .#.#.....#. .#.#.###.#. .#.#[email protected]#.#. .#.#####.#. .#.......#. .#########. ........... 11 6 ..#..#..#.. ..#..#..#.. ..#..#..### ..#..#..#@. ..#..#..#.. ..#..#..#.. 7 7 ..#.#.. ..#.#.. ###.### [email protected] ###.### ..#.#.. ..#.#.. 0 0
Sample Output
45 59 6 13