国内予選2009B 島はいくつある？ AOJ 1160

解法：幅優先探索やるだけ。
if(check[q.fs][q.sc] != 0) continue;を書き忘れてて無限にMLEくらってた

#include <bits/stdc++.h>
#define chmin(a, b) ((a)=min((a), (b)))
#define chmax(a, b) ((a)=max((a), (b)))
#define fs first
#define sc second
#define eb emplace_back
using namespace std;
 
typedef long long ll;
typedef pair<int, int> P;
typedef tuple<int, int, int> T;
 
const ll MOD=1e9+7;
const ll INF=1e18;
 
int dx[]={1, -1, 0, 0};
int dy[]={0, 0, 1, -1};

int mp[55][55];
int check[55][55];

int dx2[] = {-1,0,1,1,1,0,-1,-1};
int dy2[] = {1,1,1,0,-1,-1,-1,0};

int main(){

    while(true){
        int w,h;
        int ans = 0;
        cin >> w >> h;
        if(w + h == 0) break;
        for(int i = 0;i < h;i++){
            for(int j = 0;j < w;j++){
                cin >> mp[i][j];
                check[i][j] = 0;
            }
        }
        for(int i = 0;i < h;i++){
            for(int j = 0;j < w;j++){
                if(mp[i][j] == 1 && check[i][j] == 0){
                    ans++;
                    queue<P> que;
                    que.push(P(i,j));
                    while(!que.empty()){
                        P q = que.front(); que.pop();
                        if(check[q.fs][q.sc] != 0) continue;
                        check[q.fs][q.sc] = 1;
                        for(int k = 0;k < 8;k++){
                            int ni = q.fs + dx2[k];
                            int nj = q.sc + dy2[k];
                            if(min(ni,nj) >= 0 && ni < h && nj < w && mp[ni][nj] == 1 && check[ni][nj] == 0){
                                que.push(P(ni,nj));
                            }
                        }
                    }
                }
            }
        }
        cout << ans << endl;
    }

}