A - Red and Black(3.2.1)（搜索） - c++编程基础

A - Red and Black(3.2.1) Time Limit:1000MS Memory Limit:30000KB 64bit IO Format:%I64d & %I64u Submit Status

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

#include
   
    
#include
    
      using namespace std; int b,c,k,i,s,x,y,n; char a[21][21]; int sousuo(int x,int y,int a1,int b) { int n=0; if(x>0) if(a[x-1][y]=='.') {n++;a[x-1][y]='a';n=n+sousuo(x-1,y,a1,b);} if(y>0) if(a[x][y-1]=='.') {n++;a[x][y-1]='a';n=n+sousuo(x,y-1,a1,b);} if(x
     
      >k>>s&&k) { memset(a,'q',sizeof(a)); for(i=0;i
      
       >a[i][j]; if(a[i][j]=='@') x=i,y=j; } n=sousuo(x,y,s,k); cout<<++n<