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>
using namespace std;

int state[100][100];
bool reached[100][100];
int w,h;

int dx[8]={1,0,-1,0,1,-1,1,-1};
int dy[8]={0,1,0,-1,1,1,-1,-1};

void dfs(int x, int y) {

	if(x==0 || w<x || y==0 || h<y || state[x][y] == 0)
		return;
	if(reached[x][y] == true)
		return;

	reached[x][y]=true;

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

int main() {

	memset(state, -1, sizeof(state));
	memset(reached, false, sizeof(reached));

	cin >> w >> h;
	for(int i=1; i<=w; i++) {
		for(int j=1; j<=h; j++) {
			cin >> state[i][j];
		}
	}
	int count=0;
	for(int i=1; i<=w; i++) {
		for(int j=1; j<=h; j++) {
			if(state[i][j]==0)
				continue;
			else{
				dfs(i,j);
				count++;
			}
		}
	}
	cout << count << endl;
	return 0;
}

C++: #include <cstdio>

using namespace std;

int w, h;
int field[50][51];

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

void solve(void){
	int res = 0;
	for(int i = 0; i < h; i++){
		for(int j = 0; j < w; j++){
			if(field[i][j] == 1){
				dfs(i, j);
				res++;
			}
		}
	}
	printf("%d\n", res);
}

int main(void)
{
	while(scanf("%d %d", &w, &h) != EOF){
		if(w == 0 && h == 0){ break; }
		for(int i = 0; i < h; i++){
			for(int j = 0; j < w; j++){
				scanf("%d", &field[i][j]);
			}
		}
		solve();
	}
	
	return 0;
}

C++: #include <iostream>
#include <math.h>
#include <algorithm>
#include <vector>
using std::cin;
using std::cout;
using std::endl;
using std::string;
using std::vector;
				
				
void del_island(int i,int j,vector<vector<int>> &v){	
	v[i][j] = 0;
	if(v[i-1][j] == 1){
		del_island(i-1,j,v);
	}
	
	if(v[i+1][j] == 1){
		del_island(i+1,j,v);
	}
	if(v[i][j-1] == 1){
		del_island(i,j-1,v);
	}
	
	if(v[i][j+1] == 1){
		del_island(i,j+1,v);
	}
	if(v[i-1][j-1] == 1){
		del_island(i-1,j-1,v);
	}
	
	if(v[i-1][j+1] == 1){
		del_island(i-1,j+1,v);
	}
	
	if(v[i+1][j-1] == 1){
		del_island(i+1,j-1,v);
	}
	
	if(v[i+1][j+1] == 1){
		del_island(i+1,j+1,v);
	}

}

void mapping(vector<vector<int>>v,int w,int h){
	for(int i = 1;i <= h ; i++){
		for(int j = 0; j <= w ;j++){
			cout << v[i][j];
		}
		cout <<endl;
	}
	cout << endl;
}
void mapping2(int i, int j){
	cout << "i = " << i << endl;
	cout << "j = " << j << endl;
}
int count_island(int w, int h,vector<vector<int>> v){
	int count = 0;
	for(int i = 1 ; i <= h ;i++){
		for(int j = 1 ;j <= w ;j++){
			//cout << v[i][j] ;
			if(v[i][j] == 1){
				count++;
				//cout << "hello" <<endl;
				del_island(i,j,v);
				//mapping2(i,j);
				
			}
		}
	}
	return count;
}
	
int main(){ 
	int w,h;
	vector<vector<int>> v(60,vector<int>(60,0));
	int count;

	while(1){
		cin >> w >> h;
		if(w == 0 && h == 0){
			break;
		}
		count = 0; 
		for(int i = 1; i <= 59 ; i++){
			for(int j = 1 ; j <= 59 ; j++){
				v[i][j] = 0;
			}
		}

		for(int i = 1;i <= h; i++){
			for(int j = 1; j <= w; j++){
				cin >> v[i][j];
			}
		}

		count = count_island(w,h,v);
		//mapping(v,50,50);


		cout << count << endl;
	}
}

C++: #include <iostream>
#include <algorithm> // min()
#include <string>
#include <vector>
#include <climits> // INT_MAX
#include <cmath> // ceil()
#define rep(i, n) for (int i = 0; i < n; ++i)

using namespace std;
using ll = long long;
const int INF = INT_MAX;
using Graph = vector<vector<int>>;
using Vi = vector<int>;
using Vpii = vector<pair<int, int>>;
using Pii = pair<int, int>;


vector<bool> seen;
int ans = 0;
int land = 0;
bool is_tree = false;
Pii region;


void dfs(Graph &g, int x, int y) {
    if (x < 0 || x >= region.first) return;
    if (y < 0 || y >= region.second) return;

    if (g[y][x] == 0) return;

    if (g[y][x] == 1) {
        g[y][x] = 0;
        land--;
    }

    dfs(g, x + 1, y);
    dfs(g, x - 1, y);
    dfs(g, x, y + 1);
    dfs(g, x, y - 1);
    dfs(g, x + 1, y + 1);
    dfs(g, x + 1, y - 1);
    dfs(g, x - 1, y + 1);
    dfs(g, x - 1, y - 1);
}


int main() {
    Pii start;
    Vi answers;
    vector<Graph> graphs;
    int w, h, c;

    while (true)
    {
        Graph graph;
        land = 0;
        ans = 0;

        cin >> w >> h;
        if (w == 0 && h == 0) break;
        region = { w, h };

        rep(i, h) {
            Vi temp;
            rep(j, w) {
                cin >> c;
                temp.emplace_back(c);
                land += c;
            }
            graph.emplace_back(temp);
        }

        while (land) {
            int x;
            rep(y, h) {
                auto vec = graph[y];
                auto iter = find(vec.begin(), vec.end(), 1);
                if (iter != vec.end()) {
                    x = distance(vec.begin(), iter);
                    start = { x, y };
                    break;
                }
            }
            dfs(graph, start.first, start.second);
            ans++;
        }

        answers.emplace_back(ans);

    }

    for (auto&& a : answers) {
        cout << a << endl;
    }

}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <functional>
#include <numeric>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <utility>
#include <sstream>
#include <complex>

using namespace std;

#define FOR(i,a,b) for(long long i=(a);i<(b);i++)
#define REP(i,N) for(long long i=0;i<(N);i++)
#define ALL(s) (s).begin(),(s).end()
#define fi first
#define se second

#define PI acos(-1.0)
#define INF 1000000007
#define EPS 1e-10

typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<double, double> PD;
typedef pair<string, ll> PS;
typedef vector<ll> V;
typedef pair<P, char> PC;

int w, h;
int c[100][100];
int ans;

void solve(int y, int x){
	c[y][x] = 0;

	for (int i = -1; i <= 1; i++){
		for (int j = -1; j <= 1; j++){
			int ny = y + i, nx = x + j;
			if (ny >= 0 && ny < h&&nx >= 0 && nx < w){
				if (c[ny][nx] == 1)solve(ny, nx);
			}
		}
	}
}

int main(){
	while (cin >> w >> h&&w + h){
		REP(i, h){
			REP(j, w){
				cin >> c[i][j];
			}
		}
		ans = 0;
		REP(i, h){
			REP(j, w){
				if (c[i][j] == 1){
					solve(i, j);
					ans++;
				}
			}
		}
		cout << ans << endl;
	}
}