POJ 2386 java实现

描述：

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

import java.util.Scanner;
public class Main {


    private static char filed[][]=new char[100][100];
    public static void search(int x,int y,int n,int m){
        filed[x][y]='.';
        for(int i=-1;i<2;i++)
            for(int j=-1;j<2;j++){
                int px=x+i,py=y+j;
                if(px>=0&&py>=0&&px<n&&py<m){
                    if(filed[px][py]=='W'){
                        filed[px][py]='.';
                        Main.search(px, py, n, m);
                    }
                }
            }
    }
    public static void main(String[] args) {
        // write your code here
        int n=0,m=0;
        int num=0;   //池塘总数
        String s;
        Scanner sc = new Scanner(System.in);
        n=sc.nextInt();
        m=sc.nextInt();
        for(int i=0;i<n;i++){            //输入W和.
            s=sc.next();
            for(int j=0;j<m;j++){
                filed[i][j]=s.charAt(j);  //把W和.存入数组
            }
        }
        sc.close();
        for(int i=0;i<n;i++)
            for(int j=0;j<m;j++){
                if(filed[i][j]=='W'){
                    Main.search(i,j,n,m);
                    num++;
                }
            }
        System.out.println(num);


    }
}