Red and Black
Time Limit: 1000MS | Memory Limit: 30000K | |
Total Submissions: 30661 | Accepted: 16688 |
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 59 613
介个题就是让你求一下他能走多少个".",一个小迷宫,运用DFS,再加上一个记录数组就行啦,不过这个不能在回溯的时候将已经遍历过的变回原值。
代码在下边:
#include <cstdio> #include <cstring> #include <cmath> #include <algorithm> #include <climits> #include <queue> #define M 10000 using namespace std; char map[25][25]; bool vis[25][25]; int fx[4]={1,-1,0,0}; int fy[4]={0,0,1,-1}; int ans,w,h; void f(int x,int y) { for(int i=0;i<4;i++) { if(map[x+fx[i]][y+fy[i]]=='.'&&vis[x+fx[i]][y+fy[i]]==false&&x+fx[i]>=0&&x+fx[i]<h&&y+fy[i]>=0&&y+fy[i]<w) { vis[x+fx[i]][y+fy[i]]=true; ans++; f(x+fx[i],y+fy[i]); } } } int main() { while(~scanf("%d%d",&w,&h)&&w||h) { int x,y; memset(vis,false,sizeof(vis)); for(int i=0;i<h;i++) { getchar(); for(int j=0;j<w;j++) { scanf("%c",&map[i][j]); if(map[i][j]=='@') { vis[i][j]=true; x=i;y=j; } } } ans=0; f(x,y); printf("%d\n",ans+1); } return 0; }