POJ 2386 Lake Counting

此题就是一个深度优先搜索的实例，遍历一遍池塘，将凡是有水的周围的八个格子进行DFS使所有'W'变成'.'，这样进行了几次DFS，就有几片池塘。具体如代码。

题目链接:POJ 2386 Lake Counting

#include <iostream>

using namespace std;

#define MAX_N 100
#define MAX_M 100

char field[MAX_N][MAX_M+1];
void DFS (int n, int m);
int n, m;

int main (void)
{
    int count = 0;
    while(cin>>n>>m)
    {
        for(int i = 0; i < n; i++)
            for(int j = 0; j < m; j++)
            {
                cin>>field[i][j];
            }
        for(int i = 0; i < n; i++)
        {
            for(int j = 0; j < m; j++)
            {
                if(field[i][j] == 'W')
                {
                    DFS(i,j);
                    count++;
                }
            }
        }
        cout<<count<<endl;

    }
    return 0;
}

void DFS (int x, int y)
{
    field[x][y] = '.';
    for(int dx = -1; dx <= 1; dx++)
    {
        for(int dy = -1; dy <= 1; dy++)
        {
            int nx = x + dx;
            int ny = y + dy;
            if(nx<=n && nx>= 0 && ny<= m && ny>= 0 && field[nx][ny]=='W')
                DFS(nx,ny);
        }
    }
    return;
}