poj 2386

题意：给你一个row*col的矩阵表示一块田地，上面的'W'代表积水，'.'表示干地，问这块田地里面的积水能汇聚成几片水洼

简单的dfs,由于粗心，水和田搞反了，wa了好几次

Memory: 3848K

Time: 1500MS

import java.util.Scanner;

public class Main{
    static char map[][];
    static int n,m;
    static boolean visited[][];
    static int move[][] = {{0,0,1,-1,1,1,-1,-1},{1,-1,0,0,1,-1,1,-1}};
    
    public static boolean isIn(int x,int y){
        return x>=0&&x<n&&y>=0&&y<m;
    }
    
    public static void dfs(int x,int y){
        visited[x][y] = true;
        for(int i=0;i<8;i++){
            int tx = x + move[0][i];
            int ty = y + move[1][i];
            if(isIn(tx,ty)&&map[tx][ty]!='.'&&visited[tx][ty]==false)
                dfs(tx,ty);
        }
    }
    
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        n = in.nextInt();
        m = in.nextInt();
        in.nextLine();
        map = new char[n][m];
        visited = new boolean[n][m];
        for(int i=0;i<n;i++){
            map[i] = in.nextLine().trim().toCharArray();
        }
        int num=0;
        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                if(map[i][j]=='W'&&visited[i][j]==false)
                {
                    dfs(i,j);
                    num++;
                }
            }
        }
        System.out.print(num);
    }
}