[ACM]Uva572-Oil Deposits-DFS应用

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>

using namespace std;

const int maxn = 100 + 5;

char piece[maxn][maxn];
int n,m,idx[maxn][maxn];

void dfs(int r, int c, int id)
{
	if(r<0 || r>=m || c<0 || c>=n)	return;
	if(idx[r][c] > 0 || piece[r][c]!='@')	return;
	idx[r][c]=id;
	for(int dr=-1; dr<=1;dr++)//dfs式探索
		for(int dc=-1;dc<=1;dc++)
			if(dr!=0 || dc!=0)	dfs(r+dr, c+dc, id);
}

int main(){
	while(scanf("%d%d", &m, &n) == 2 && m && n)
	{
		for(int i=0;i<m;i++)
		{
			cin>>piece[i];
		}
		memset(idx, 0 ,sizeof(idx));
		int cur=0;
		for(int i=0;i<m;i++)
		{
			for(int j=0;j<n;j++)
			{
				if(idx[i][j]==0 && piece[i][j] == '@')
					dfs(i,j,++cur);
			}
		}
		cout<<cur<<endl;
	}
	return 0;
}