red and black(BFS)
Red and Black
Time Limit: 1000MS | Memory Limit: 30000K | |
Total Submissions: 40685 | Accepted: 22079 |
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)
The end of the input is indicated by a line consisting of two zeros.
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
题解:简单的BFS
AC代码
1 #include<stdio.h> 2 #include<iostream> 3 #include<stdio.h> 4 #include<string> 5 #include<cmath> 6 #include<algorithm> 7 using namespace std; 8 9 char a[25][25]; 10 int w, h; 11 int ant; 12 13 void dfs(int x, int y) 14 { 15 if(a[x][y] != '#' && x >= 0 && x < h && y >= 0 && y < w) 16 { 17 ant++; 18 a[x][y] = '#'; 19 dfs(x+1, y); 20 dfs(x-1, y); 21 dfs(x, y+1); 22 dfs(x, y-1); 23 } 24 } 25 26 int main() 27 { 28 while(scanf("%d%d", &w, &h) != EOF) 29 { 30 ant = 0; 31 if(w == 0 && h == 0) 32 break; 33 for(int i = 0; i < h; i++) 34 { 35 for(int j = 0; j < w; j++) 36 { 37 cin >> a[i][j]; 38 } 39 } 40 for(int i = 0; i < h; i++) 41 for(int j = 0; j < w; j++) 42 if(a[i][j] == '@') 43 dfs(i, j); 44 cout << ant << endl; 45 } 46 return 0; 47 }
永远渴望,大智若愚(stay hungry, stay foolish)