POJ 2386 Lake Counting

Description

Due to recent rains, water has pooled in various places in Farmer John's field, which is represented by a rectangle of N x M (1 <= N <= 100; 1 <= M <= 100) squares. Each square contains either water ('W') or dry land ('.'). Farmer John would like to figure out how many ponds have formed in his field. A pond is a connected set of squares with water in them, where a square is considered adjacent to all eight of its neighbors.

Given a diagram of Farmer John's field, determine how many ponds he has.

Input

* Line 1: Two space-separated integers: N and M

* Lines 2..N+1: M characters per line representing one row of Farmer John's field. Each character is either 'W' or '.'. The characters do not have spaces between them.

Output

* Line 1: The number of ponds in Farmer John's field.

Sample Input

10 12W........WW..WWW.....WWW....WW...WW..........WW..........W....W......W...W.W.....WW.W.W.W.....W..W.W......W...W.......W.

Sample Output

3

Hint

OUTPUT DETAILS:

There are three ponds: one in the upper left, one in the lower left,and one along the right side.

问题描述：

有一个大小为N*M的园子，雨后积了很多水。八连通的积水被认为是在一起的。请求出园子里共有多少个水洼？(八连通是指下图中相对.的W部分)

WWW

W  .   W

WWW

限制条件：

N,M <= 100

#include<iostream>#include<cstdio>#include<cstdlib>const int maxn=110;using namespace std;struct node{int x,y;};node q[maxn*maxn];int a[maxn][maxn];char s[maxn];int d[8][2]={{1,0},{0,1},{-1,0},{0,-1},{1,-1},{1,1},{-1,1},{-1,-1}};void dfs(int x,int y){a[x][y]=0;for(int i=0;i<8;i++){int u=x+d[i][0];int v=y+d[i][1];if(a[u][v])dfs(u,v);}}int main(){int i,j,k,m,n,ans=0;cin>>n>>m;getchar();for(i=1;i<=n;i++){gets(s);for(j=0;j<m;j++)if(s[j]=='W')a[i][j+1]=1;}for(i=1;i<=n;i++)for(j=1;j<=m;j++)if(a[i][j]==1){ans++;dfs(i,j);}cout<<ans<<endl;return 0;}