【紫书】Oil Deposits UVA - 572 dfs求联通块

#define _CRT_SECURE_NO_WARNINGS
#include "stdio.h"
#include<stdio.h>
#include<algorithm>
#include<string>
#include<vector>
#include<list>
#include<set>
#include<iostream>
#include<string.h>
#include<queue>
#include<string>
#include<sstream>
using namespace std;
const int maxn = 100+5;
string map[maxn];
int ans;
int idx[maxn][maxn];
int n, m;
void dfs(int r,int c,int id) {
    if (r<0||c<0||r>=n||c>=m||map[r][c] == ‘*‘||idx[r][c])return;
    idx[r][c] = id; 
    for(int dr=-1;dr<=1;dr++)
        for (int dc = -1; dc <= 1; dc++) 
            if(dr||dc)dfs(r + dr, c + dc,id);
}
int main(){
    
    while (cin >> n >> m) {
        if (n == 0 && m == 0)break;
        ans = 0;
        memset(idx, 0, sizeof(idx));
        for (int i = 0; i < n; i++) {
            cin >> map[i];
        }
        for (int i = 0; i < n; i++)
            for (int j = 0; j < m; j++)
                if (idx[i][j] == 0 && map[i][j] == ‘@‘) dfs(i, j, ++ans);
        cout << ans<<endl;
    }
    return 0;
}