2015AC小分队训练赛（二）--J（杭电1312）

Red and Black

Time Limit: 2000/1000 MS (Java/Others)    Memory
Limit: 65536/32768 K (Java/Others)

Total Submission(s): 11051    Accepted Submission(s): 6913

Problem 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) 

 

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

Asia 2004, Ehime (Japan), Japan Domestic

题目意思：
有一个矩形的房间，里面铺满了方形的瓷砖。每一个瓷砖有红色还有黑色两种，人只能站在黑色的瓷砖上不能站在红色的瓷砖上，每次只能走前后左右四个方向的四个瓷砖，计算能够到达的黑色瓷砖的总面积数，实际上就是搜素连同块，最简单的搜索。