Go: ///
// File:  1160.go
// Author: ymiyamoto
//
// Created on Sun Mar  4 20:45:57 2018
//
package main

import (
	"fmt"
)

var w, h int
var graph [][]string

func dfs(visited [][]bool, x, y int) {
	visited[x][y] = true

	for i := -1; i <= 1; i++ {
		for j := -1; j <= 1; j++ {
			dx := x + i
			dy := y + j
			if 0 <= dx && dx < h && 0 <= dy && dy < w && graph[dx][dy] == "1" && !visited[dx][dy] {
				dfs(visited, dx, dy)
			}
		}
	}
}

func main() {
	for {
		fmt.Scan(&w, &h)
		if w == 0 && h == 0 {
			break
		}

		graph = make([][]string, h)
		for i := range graph {
			graph[i] = make([]string, w)
		}

		for i := 0; i < h; i++ {
			for j := 0; j < w; j++ {
				var s string
				fmt.Scan(&s)
				graph[i][j] = s
			}
		}

		visited := make([][]bool, h)
		for i := range visited {
			visited[i] = make([]bool, w)
		}

		count := 0
		for i := range graph {
			for j := range graph[i] {
				if graph[i][j] == "1" && !visited[i][j] {
					dfs(visited, i, j)
					count++
				}
			}
		}

		fmt.Println(count)
	}
}

C++: #include<iostream>
#include<queue>
#include<utility>
using namespace std;

int W,H;
int c[51][51]={0};
int d[51][51]={0};
int island=0;

bool valid(pair<int,int> a){
    return (a.first>=1 && a.first<=W && a.second>=1 && a.second<=H);
}

template<typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val){
    std::fill( (T*)array, (T*)(array+N), val );
}

void bfs(pair<int,int> s){
    queue<pair<int,int>> Q;

    if(c[s.first][s.second]==1 && d[s.first][s.second]==0 && valid(s)){
        Q.push(s);
        d[s.first][s.second]=1;
        ++island;

        while(!Q.empty()){
            pair<int,int> cur=Q.front();
            Q.pop();

            for(int i=-1;i<=1;++i){
                for(int j=-1;j<=1;++j){
                    pair<int,int> dst=make_pair(cur.first+i,cur.second+j);

                    if(d[dst.first][dst.second]==0 && c[dst.first][dst.second]==1 && valid(dst)){
                        Q.push(dst);
                        d[dst.first][dst.second]=1;
                    }
                }
            }
        }
    }
}

int main(){
    
    while(cin>>W>>H && W!=0){
        for(int i=1;i<=H;++i){
            for(int j=1;j<=W;++j){
                cin>>c[j][i];
            }
        }

        for(int i=1;i<=W;++i){
            for(int j=1;j<=H;++j){
                pair<int,int> start=make_pair(i,j);
                bfs(start);
            }
        }
        cout<<island<<"\n";
        island=0;
        Fill(c,0);
        Fill(d,0);
    }
}

C++: #include <bits/stdc++.h>
using namespace std;

template <class T>
void readVector(int n, vector<T> &v){
	for(int i=0; i<n; ++i){
		T t;
		cin >> t;
		v.push_back(t);
	}
}
int dx[8] = {0, 1, 1, 1, 0, -1, -1, -1};
int dy[8] = {1, 1, 0, -1, -1, -1, 0, 1};
typedef pair<long long, long long> P;

void solve(int w, int h){
	vector<int> v[h];
	for(int i=0; i<h; ++i)
		readVector(w, v[i]);
	int ans = 0;
	for(int i=0; i<h; ++i)
		for(int j=0; j<w; ++j){
			if(v[i][j] == 1){
				++ans;
				v[i][j] = 0;
				queue<P> q;
				q.push(P(i, j));
				while(!q.empty()){
					P p = q.front();
					q.pop();
					int nx = p.first;
					int ny = p.second;
					for(int k=0; k<8; ++k)
						if(0<=nx+dx[k] && nx+dx[k]<h && 0<=ny+dy[k] && ny+dy[k]<w && v[nx+dx[k]][ny+dy[k]] == 1){
							v[nx+dx[k]][ny+dy[k]] = 0;
							q.push(P(nx+dx[k], ny+dy[k]));
						}
				}
			}
		}
	cout << ans << "\n";
}

int main(){
//	cin.tie(0);
//	ios::sync_with_stdio(false);
	while(1){
		int w, h;
		cin >> w >> h;
		if(w == 0 && h == 0) return 0;
		solve(w, h);
	}
}

C++: #include <iostream>
#include <queue>
using namespace std;

int map[20][20];

typedef pair<int, int> pxy;

int h, w, ans = 0;

const int dx[] = {1, 0, -1, 0, 1, 1, -1, -1}, dy[] = {0, 1, 0, -1, -1, 1, 1, -1}; 

void bfs(int sx, int sy)
{
  queue<pxy> q;
  q.push(pxy(sx, sy)); 
  while(!q.empty()){
    int x, y;
    x = q.front().first;
    y = q.front().second;
    q.pop();
    if(map[x][y]){
      map[x][y] = 0;
      for(int i = 0; i < 8; i++){
	int next_x = x + dx[i], next_y = y + dy[i];
	if(map[next_x][next_y] && next_x < w && next_x >= 0 && next_y < h && next_y >= 0){
	  q.push(pxy(next_x, next_y));
	}
      }
    }
  }
}

int main()
{
  while(1){
    cin >> w >> h;
    if(w == 0 && h == 0){
      break;
    }else{
      for(int i = 0; i < h; i++)
	for(int j = 0; j < w; j++)
	  cin >> map[j][i];
      for(int i = 0; i < h; i++)
	for(int j = 0; j < w; j++)
	  if(map[j][i]){
	    ans++;
	    bfs(j, i);
	  }
      cout << ans << endl;
      ans = 0;
    }
  }
}

C++: #include <bits/stdc++.h>
using namespace std;

const int dx[8]={1,0,-1,0,1,1,-1,-1};
const int dy[8]={0,1,0,-1,1,-1,1,-1};
bool seen[50][50];
void dfs(vector<vector<int>> C, int h, int w, int a, int b){
    seen[a][b]=true;
    for (int i=0; i<8; i++) {
        int aa=a+dx[i];
        int bb=b+dy[i];
        if (aa<0 || bb<0 || aa>=h || bb>=w) continue;
        if (C[aa][bb]==0) {
            continue;
        }
        if (seen[aa][bb]==true) continue;
        dfs(C,h,w,aa,bb);
    }
}

int main() {
    int w,h;
   cin >> w >> h;
   int total=0;
   vector<int> x;
   while(w!=0 || h!=0) {
       total++;
   vector<vector<int>> C(h,vector<int>(w));
   for (int i=0; i<h; i++) {
       for (int j=0; j<w; j++) {
           int p;
           cin >> p;
           C[i][j]=p;
       }
   }
   int count=0;

   for (int i=0; i<h; i++) {
       for (int j=0; j<w; j++) {
           seen[i][j]=false;
       }
   }

   for (int i=0; i<h; i++) {
       for (int j=0; j<w; j++) {
           if (seen[i][j]==true) continue;
           if (C[i][j]==0) continue;
           count++;
           dfs(C,h,w,i,j);
           
       }
   }


   x.push_back(count);
   int a,b;
   cin >> a >> b;
   w=a,h=b;
   }
   for (int i=0; i<total; i++) {
       cout << x[i] << endl;
   }
}

C++: #include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<numeric>
#include<map>
#include<unordered_map>
#include<set>
#include<stack>
#include<queue>
#include<sstream>
#include<iomanip>

#define reps(i,j,k) for(int i=(j);i<(k);i++)
#define rep(i,j) reps(i,0,j)
#define fs first
#define sc second
#define pb push_back
#define mk make_pair

using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;

template<class S,class T>
ostream &operator<<(ostream &out, const pair<S,T> p){
	return out << "(" << p.fs << ", " << p.sc << ")";
}

template<class T>
ostream &operator<<(ostream &out, const vector<T> &v){
	out << "{";
	rep(i,v.size()) out << v[i] << ", ";
	return out << "}" << endl;
}
int c[50][50];
int main(){
	int w,h;
	int dx[] = {-1,  0,  1, -1, 1, -1, 0, 1};
	int dy[] = {-1, -1, -1,  0, 0,  1, 1, 1};
	while(cin >> w >> h, w){
		rep(i,h) rep(j,w) {
			cin >> c[i][j];
		}
		int cnt = 2;
		rep(i,h) rep(j,w){
			if(c[i][j] != 1) continue;
			c[i][j] = cnt;
			queue<pii> q;
			q.push(pii(i, j));
			while(!q.empty()){
				int x = q.front().sc, y = q.front().fs;
				q.pop();
				rep(k,8){
					int cx = x + dx[k], cy = y+dy[k];
					if(cx >= 0 && cy >= 0 && cy < h && cx < w && c[cy][cx] == 1){
						q.push(pii(cy, cx));
						c[cy][cx] = cnt;
					}
				}
			}
			cnt ++;
		}
		cout << cnt - 2 << endl;
	}
	return 0;
}