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>
using namespace std;
struct Point
{
	int x;
	int y;
	Point(int x = 0, int y = 0) :x(x), y(y) {}
};
const int MAX = 50;
int map[MAX][MAX];
bool book[MAX][MAX];
void depthFSearch(int h, int w, Point start)
{
	int next[9][2] = { { -1,-1 },{ -1,0 },{ -1,1 },{ 0,-1 },{ 0,0 },{ 0,1 },{ 1,-1 },{ 1,0 },{ 1,1 } };
	for (int k = 0; k <= 8; k++)
	{
		int nx = start.x + next[k][0];
		int ny = start.y + next[k][1];
		if (nx < 0 || nx >= h || ny < 0 || ny >= w || !map[nx][ny])
			continue;
		if (!book[nx][ny] && map[nx][ny])
		{
			book[nx][ny] = true;
			Point p = { nx,ny };
			depthFSearch(h, w, p);
		}
	}
	return;
}
int main()
{
	while (true)
	{
		int w, h;
		cin >> w >> h;
		if (!w && !h)
			break;
		for (int i = 0; i < h; i++)
			for (int j = 0; j < w; j++)
			{
				cin >> map[i][j];
				book[i][j] = false;
			}
		int sum = 0;
		for (int i = 0; i < h; i++)
			for (int j = 0; j < w; j++)
			{
				if (!book[i][j] && map[i][j])
				{
					book[i][j] = true;
					Point start(i, j);
					depthFSearch(h, w, start);
					sum++;
				}
			}
		cout << sum << endl;
	}
}

C++: #include<stdio.h>
#include<iostream>
#include<string>
using namespace std;

int main(){

	
	int w,h;
	while(1){
		cin>>w>>h;if(w==0&&h==0)break;
		int n[51][51]={};
	bool N[51][51]={};
		for(int i=0;i<h;i++)
			for(int j=0;j<w;j++)
			{int x;cin>>x;if(x==1)N[i][j]=true;}

		int c=0;
		for(int i=0;i<h;i++)
			for(int j=0;j<w;j++)
			{if(N[i][j]==true&&n[i][j]==0){
				c++;
				n[i][j]=c;
				if(n[i-1][j+1]==0)n[i-1][j+1]=c;
				if(n[i-1][j]==0)n[i-1][j]=c;
				if(n[i-1][j-1]==0)n[i-1][j-1]=c;
				if(n[i][j+1]==0)n[i][j+1]=c;
				if(n[i-1][j]==0)n[i-1][j]=c;
				if(n[i+1][j+1]==0)n[i+1][j+1]=c;
				if(n[i+1][j]==0)n[i+1][j]=c;
				if(n[i+1][j-1]==0)n[i+1][j-1]=c;
			}
			else if(N[i][j]==true&&n[i][j]>0){
				int y=n[i][j];
				n[i-1][j+1]=y;
				n[i-1][j]=y;
				n[i-1][j-1]=y;
				n[i][j+1]=y;
				n[i-1][j]=y;
				n[i+1][j+1]=y;
				n[i+1][j]=y;
				n[i+1][j-1]=y;
			}
			}

			for(int i=0;i<h;i++){
			for(int j=0;j<w;j++){
				int t=n[i][j];
				if(N[i][j]==true&&N[i][j+1]==true&&t>n[i][j+1])t=n[i][j+1];
				if(N[i][j]==true&&N[i][j-1]==true&&t>n[i][j-1])t=n[i][j-1];
				if(N[i][j]==true&&N[i+1][j+1]==true&&t>n[i+1][j+1])t=n[i+1][j+1];
				if(N[i][j]==true&&N[i+1][j]==true&&t>n[i+1][j])t=n[i+1][j];
				if(N[i][j]==true&&N[i+1][j-1]==true&&t>n[i+1][j-1])t=n[i+1][j-1];
				if(N[i][j]==true&&N[i-1][j+1]==true&&t>n[i-1][j+1])t=n[i-1][j+1];
				if(N[i][j]==true&&N[i-1][j]==true&&t>n[i-1][j])t=n[i-1][j];
				if(N[i][j]==true&&N[i-1][j-1]==true&&t>n[i-1][j-1])t=n[i-1][j-1];
				if(n[i][j]>t){
					for(int ii=0;ii<h;ii++)
			for(int jj=0;jj<w;jj++){
				if(n[i][j]==n[ii][jj])n[ii][jj]=t;
			}
				}
			}
			}

			int max=0;
			for(int i=0;i<h;i++){
			for(int j=0;j<w;j++){
				if(N[i][j]==true&&n[i][j]>max)max=n[i][j];
			}}
			cout<<max<<endl;
			}
return 0;
}

C++: #include <iostream>
#include <queue>
#include <stdio.h>

using namespace std;

#define NUM 50

int w, h;
int c[NUM][NUM];
bool visited[NUM][NUM];
queue<pair<int, int> > Q;

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

bool can_visit(int i, int j){
    if(i < 0 || h <= i || j < 0 || w <= j){
        return false;
    }
    if(visited[i][j] || c[i][j] == 0){
        return false;
    }
    return true;
}

pair<int, int> find_new_place(){
    for(int i = 0; i < h; i++){
        for(int j = 0; j < w; j++){
            if(can_visit(i, j)){
                return make_pair(i, j);
            }
        }
    }

    return make_pair(-1, -1);
}

bool exec(void){
    scanf("%d %d", &w, &h);
    if(w == 0 && h == 0){
        return false;
    }

    init();

    for(int i = 0; i < h; i++){
        for(int j = 0; j < w; j++){
            scanf("%d", &c[i][j]);
        }
    }

    int count = 0;

    while(true){
        pair<int, int> new_place = find_new_place();
        if(new_place.first == -1){
            break;
        }

        count++;

        Q.push(new_place);
        visited[new_place.first][new_place.second] = true;
        while(!Q.empty()){
            pair<int, int> p = Q.front(); Q.pop();
            int x = p.first;
            int y = p.second;

            vector<pair<int, int> > v;
            v.push_back(make_pair(x, y + 1));
            v.push_back(make_pair(x, y - 1));
            v.push_back(make_pair(x + 1, y + 1));
            v.push_back(make_pair(x + 1, y));
            v.push_back(make_pair(x + 1, y - 1));
            v.push_back(make_pair(x - 1, y + 1));
            v.push_back(make_pair(x - 1, y));
            v.push_back(make_pair(x - 1, y - 1));

            for(auto&& item : v){
                int x_ = item.first;
                int y_ = item.second;
                if(can_visit(x_, y_)){
                    visited[x_][y_] = true;
                    Q.push(make_pair(x_, y_));
                }
            }
        }
    }

    printf("%d\n", count);

    return true;
}

int main(void){
    while(exec()){
        ;
    }
    
    return 0;
}

C++: #include <stdio.h>

	int sima[50][50];
	int cnt=0;
	int cflag=0;

int count_sima(int w,int h){
	if(w<0)return 0;
	if(h<0)return 0;
	if(sima[w][h]==3)return 0;
	if(sima[w][h]==0)return 0;

		if(cflag==0){
			cnt++;
			cflag=1;
		}
		

		sima[w][h]=0;

		count_sima(w,h+1);
		count_sima(w+1,h+1);
		count_sima(w+1,h);
		count_sima(w+1,h-1);
		count_sima(w,h-1);
		count_sima(w-1,h-1);
		count_sima(w-1,h);
		count_sima(w-1,h+1);


	return 0;
}


int main(void){
	int w2,h2; //島の大きさを格納する
	int p;

	scanf("%d %d",&w2,&h2);
	while(w2!=0 && h2!=0){

		//島配列をすべてを3にする
		for(int i=0; i<50; i++){
			for(int j=0; j<50; j++){
				sima[i][j]=3;
			}
		}

		//入力された地図のデータを設定
		for(int i=0; i<h2; i++){
			for(int j=0; j<w2; j++){
				scanf("%d",&p);
				sima[i][j]=p;
			}
		}

		//ここまで入力された地図のデータを設定

		for(int i=0; i<h2; i++){
			for(int j=0; j<w2; j++){
				count_sima(i,j);
				cflag=0;
			}
		}

		printf("%d\n",cnt);
		cnt=0;

		scanf("%d %d",&w2,&h2);
	}

	return 0;
}