搜索：poj 3620 Avoid The Lakes（DFS）

【转】http://blog.youkuaiyun.com/zxy_snow/article/details/5947541

 

#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <memory.h>
using namespace std;
int map[110][110],visit[110][110];
int m,n,num,mmax,fi,fj,cou;
int dir[8] = {0,1,0,-1,1,0,-1,0};
int find()
{
	for(int i=1; i<=m; i++)
		for(int j=1; j<=n; j++)
			if( !visit[i][j] && map[i][j] )
			{
				fi = i;
				fj = j;
				return 1;
			}
	return 0;
}
void DFS(int i,int j)
{
	for(int k=0; k<8; k+=2)
	{
		int a = i + dir[k];
		int b = j + dir[k+1];
		if( a>=1 && a<=m && b>=1 && b<=n && !visit[a][b] && map[a][b] )
		{
			visit[a][b] = 1;
			DFS(a,b);
			cou++;
		}
	}
}
int main(void)
{
	int x,y;
	while( cin >> m >> n >> num )
	{
		mmax = 0; cou = 0;
		memset(map,0,sizeof(map));
		memset(visit,0,sizeof(visit));
		for(int i=1; i<=num; i++)
		{
			cin >> x >> y;
			map[x][y] = 1;
		}
		while( find() )
		{
		    visit[fi][fj] = 1;
		    cou = 1;
			DFS(fi,fj);
			if( cou > mmax )
			    mmax = cou;
		}
		cout << mmax << endl;
	}
return 0;
}