poj_2386 DFS

题意：算出有多少个池塘的。

转换-> 有多少个连通的W区域 + 8方向搜索

code：

<span style="font-size:18px;">#include <iostream>
#include <fstream>

using namespace std;

int n, m,result;
int map[110][110], visit[110][110];
int dir[8][2] = {
		{-1,-1},
		{ 0,-1},
		{ 1,-1},
		{-1, 0},
		{ 1, 0},
		{-1, 1},
		{ 0, 1},
		{ 1, 1},
};
int fi, fj;
//fstream in("input.txt");

int find()
{
	for (int i = 1; i <= n; i++)
	{
		for (int j = 1; j <= m; j++)
		{
			//not visit && is W
			if (!visit[i][j] && map[i][j] == 1)
			{
				fi = i;
				fj = j;
				return 1;
			}
		}
	}
	return 0;
}

void input()
{
	char s[110];
	for (int i = 1; i <= n; i++)
	{
		cin >> s;
		for (int j = 0; j < m; j++)
		{
			// W -> 1   ,   land -> 0
			map[i][j + 1] = (s[j] == 'W' ? 1 : 0);
		}
	}
}

void dfs(int i, int j)
{
	//traverse 8 directions
	for (int k = 0; k < 8; k++)
	{
		int newi = i + dir[k][0];
		int newj = j + dir[k][1];
		if (newi >= 1 && newi <= n && newj >= 1 && newj <= m && !visit[newi][newj] && map[newi][newj] == 1)
		{
			visit[newi][newj] = 1;
			dfs(newi,newj);
		}
	}
}

int main()
{
	while (cin >> n >> m)
	{
		memset(visit,0,sizeof(visit));
		result = 0;
		input();
		while (find())
		{
			visit[fi][fj] = 1;
			dfs(fi,fj);
			result++;
		}
		cout << result << endl;
	}
	//system("pause");
	return 0;
}
</span>