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 <bits/stdc++.h>
#include <math.h>
#define ALL(a)    a.begin(), a.end()
using namespace std;

vector<vector<int>> V;
vector<int> dx{0, 0, 1, 1, 1, -1, -1, -1};
vector<int> dy{1, -1, 0, 1, -1, 0, 1, -1};
vector<vector<bool>> seen;
int W = 1, H = 1, Ans = 0;


void dfs(int y, int x){
seen[y][x] = 1;

for(int i = 0; i < 8; i++){
int ny = y + dy[i], nx = x + dx[i];

if(ny < 0 || ny >= H || nx < 0 || nx >= W)continue;

if(V[ny][nx] == 0)continue;

if(seen[ny][nx])continue;

dfs(ny, nx);
}



}


int main() {


while(1){

cin >> W >> H;
if(H == 0 && W == 0)break;

V.resize(H);
seen.resize(H);

for(int i = 0; i < H; i++){
V[i].resize(W);seen[i].resize(W);}

for(int i = 0; i < H; i++){
for(int j = 0; j < W; j++){
cin >> V[i][j];
//cout << V.at(i).at(j);
seen[i][j] = 0;
}}

for(int i = 0; i < H; i++){
for(int j = 0; j < W; j++){
if(V[i][j] == 1 && seen[i][j] == 0){dfs(i, j);Ans++;}
}}
cout << Ans << endl;
Ans = 0;
}


}

C++: #include <bits/stdc++.h>
#include <math.h>

using namespace std;

long long inf=1000000007;
long long h,w;

void dfs(long long y,long long x,vector<vector<bool>> &seen,vector<vector<long long>> grid){
	vector<long long> dy={1,1,1,0,0,-1,-1,-1};
	vector<long long> dx={1,0,-1,1,-1,1,0,-1};

	for(long long i=0;i<8;i++){
		long long py=y+dy.at(i);
		long long px=x+dx.at(i);

		if(py<0 || py>=h || px<0 || px>=w || grid.at(py).at(px)==0 || seen.at(py).at(px)) continue;

		seen.at(py).at(px)=true;
		dfs(py,px,seen,grid);
	}
}

int main(){
	cin>>w>>h;

	while(h!=0 || w!=0){
		vector<vector<long long>> grid(h,vector<long long>(w));
		for(long long i=0;i<h;i++){
			for(long long j=0;j<w;j++){
				cin>>grid.at(i).at(j);
			}
		}

		vector<vector<bool>> seen(h,vector<bool>(w,false));
		long long ans=0;

		for(long long i=0;i<h;i++){
			for(long long j=0;j<w;j++){
				if(grid.at(i).at(j)==0 || seen.at(i).at(j)) continue;
				ans++;
				seen.at(i).at(j)=true;
				dfs(i,j,seen,grid);
			}
		}

		cout<<ans<<endl;
		cin>>w>>h;
	}

	return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <map>
#include <cmath>
#include <string>
#include <sstream>
#include <iomanip>
#include <complex>
using namespace std;
 
#define ll long long
#define vvi vector< vector<int> >
#define All(X) X.begin(),X.end()
#define FOR(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define REP(i,n) for(int i=0;i<(int)(n);i++)
#define pb push_back 
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
ll lcm(ll a,ll b){return a/gcd(a,b)*b;}

int w,h;
int c[100][100];
bool notsearched[100][100];
int dx[8]={0,1,0,-1,1,1,-1,-1};
int dy[8]={1,0,-1,0,1,-1,1,-1};
int ans;

bool inrange(int x, int y){
  if(x<0||y<0||x>=h||y>=w){ 
	//cout << "false" <<endl;
	return false;
  }else{ 
	//cout << "true" << endl;
	return true;
  }
}

void search(int x, int y){

  if((notsearched[x][y])&&(c[x][y] == 1)&&(inrange(x,y))){
	notsearched[x][y]=false;

	REP(i,8) search(x+dx[i],y+dy[i]);
  }
}


int main(){
  while(1){

	REP(i,100){
	  REP(j,100){
		notsearched[i][j]=true;
	  }
	}

	cin >> w >> h;
	if (w==0&&h==0) break;
	ans=0;
	REP(i,h){
	  REP(j,w){
		cin >> c[i][j];

	  }
	}

	REP(i,h){
	  REP(j,w){
		if((notsearched[i][j])&&(c[i][j] == 1)&&(inrange(i,j))) ans++; 
		search(i,j);
	  }
	}
	cout << ans << endl;
  }
 
}

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

int w, h;
int c[50][50];

void dfs(int x, int y) {
  c[x][y] = 0;
  for (int dx = -1; dx <= 1; dx++) {
    for (int dy = -1; dy <= 1; dy++) {
      int nx = x + dx, ny = y + dy;
      if (0 <= nx && nx < h && 0 <= ny && ny < w && c[nx][ny] == 1)
        dfs(nx, ny);
    }
  }
  return;
}

int main() {
  while (true) {
    cin >> w >> h;
    if (w == 0 && h == 0) break;
    for (int i = 0; i < h; i++)
      for (int j = 0; j < w; j++)
        cin >> c[i][j];
    int islands = 0;
    for (int i = 0; i < h; i++) {
      for (int j = 0; j < w; j++) {
        if (c[i][j] == 1) {
          islands++;
          dfs(i, j);
        }
      }
    }
    cout << islands << endl;
  }
  return 0;
}

C++: #include<iostream>
#include<iomanip>
#include<algorithm>
#include<cstdio>
#include<cmath>
#include<map>
#include<numeric>
#include<set>
#include<string>
#include<utility>
#include<vector>
#include<queue>


#define rep(i, a, n)  for(int i=a; i<n; i++)
#define per(i, a, n)  for(int i=n-1; i>=a; i--)
#define fill0(n)  setfill('0') << right << setw(n)
#define all(x)  (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define MAX 1000001
using namespace std;
typedef long long ll;

int w,h;
int c[51][51];

void dfs(int y,int x){
  if(y<1||51<=y||x<1||51<=x||c[y][x]==0)return;
  c[y][x]=0;
  dfs(y-1, x-1);
  dfs(y-1, x);
  dfs(y-1, x+1);
  dfs(y, x-1);
  dfs(y, x+1);
  dfs(y+1, x-1);
  dfs(y+1, x);
  dfs(y+1, x+1);
}

int main(){
  while(true){
    std::cin >> w>>h;
    if(w==0&&h==0)break;
    rep(i,1,h+1){
      rep(j,1,w+1){
        std::cin >> c[i][j];
      }
    }
    int res=0;
    rep(i,1,h+1){
      rep(j,1,w+1){
        // std::cout << c[1][1] << '\n';
        if(c[i][j]==1){
          // std::cout << "/* message */" << '\n';
          dfs(i,j);
          res++;
        }
      }
    }
    std::cout << res << '\n';
  }
  return 0;
}

C++: #include<iostream>
#include<vector>

using namespace std;

int w,h;
bool field[50][50];
vector<int> ans;

void dfs(int i,int j);

int main(){
	while(1){
		for(int i = 0;i < 50;i++){
			for(int j = 0;j < 50;j++){
				field[i][j] = false;
			}
		}
		cin >> w >> h;
		if(w + h == 0) break;
		for(int i = 0;i < h;i++){
			for(int j = 0;j < w;j++){
				int f;
				cin >> f;
				if(f == 1) field[i][j] = true;
			}
		}
		int count = 0;
		for(int i = 0;i < h;i++){
			for(int j = 0;j < w;j++){
				if(field[i][j]){dfs(i,j);count++;}
			}
		}
		ans.push_back(count);
	}
	for(int i = 0;i < ans.size();i++) cout << ans[i] << endl;
	return 0;
}

void dfs(int i,int j){
	field[i][j] = false;
	if(i != 0 	&& j != 0 	&& field[i-1][j-1])dfs(i-1,j-1);
	if(i != 0 				&& field[i-1][j])dfs(i-1,j);
	if(i != 0 	&& j != w-1 && field[i-1][j+1])dfs(i-1,j+1);
	if(			   j != w-1 && field[i][j+1])dfs(i,j+1);
	if(i != h-1 && j != w-1 && field[i+1][j+1])dfs(i+1,j+1);
	if(i != h-1 			&& field[i+1][j])dfs(i+1,j);
	if(i != h-1 && j != 0 	&& field[i+1][j-1])dfs(i+1,j-1);
	if(			   j != 0 	&& field[i][j-1])dfs(i,j-1);
}