本文共 2230 字，大约阅读时间需要 7 分钟。
| Time Limit: 1000MS | | Memory Limit: 30000K |
| Total Submissions: 24058 | | Accepted: 13007 |
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
4559613
题意：问从@出发可以到的点的个数
简单搜索！！！
参考代码：
#include #include #include using namespace std;typedef long long ll;char map[22][22];bool used[22][22];int dp[22][22];int n,m;int dirx[]={ 0,-1,0,1};int diry[]={-1, 0,1,0};int dfs(int x,int y){ int sum=0; if (used[x][y]==true) return 0; if (dp[x][y]!=0) return dp[x][y]; used[x][y]=true; for (int i=0;i<4;i++){ int xx=x+dirx[i],yy=y+diry[i]; if (map[xx][yy]=='.' && used[xx][yy]==false && xx =0 && yy =0){ sum+=dfs(xx,yy); } } dp[x][y]=sum+1; return sum+1;}int main(){ while (cin>>n>>m){ if (n==0&&m==0) break; int x,y; memset(used,false,sizeof(used)); memset(dp,0,sizeof(dp)); for (int i=0;i >map[i][j]; if (map[i][j]=='@'){ x=i; y=j; } } } cout< <
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