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<iostream>
#define rep(i,n) for(int i=0;i<n;++i)
#define rrep(i,n) for(int i=n-1;i>=0;--i)
#define yesno(flg) if(flg){cout<<"YES"<<endl;}else{cout<<"NO"<<endl;}
#define MAX_N 1002
#define i197 1000000007

using namespace std;
typedef long long ll;
typedef pair<ll,ll> P1;
typedef pair<int,int> Pi;
typedef pair<double,Pi> Pdi;
typedef pair<ll,int>Pli;
typedef pair<int,ll>Pil;
typedef pair<P1,ll> P2;
typedef pair<string,string> Ps;
const ll INF=1000000000000000001;
struct edge{int to,cost;};
int dy[]={0, 0, 1, -1};
int dx[]={1, -1, 0, 0};
struct Road{double cost;int a,b;};
struct pos{
	// 1 変数を入れる;
	int x,y;
};

int main() {

	while(1){
		int w,h;
		cin>>w>>h;
		if(w==0&&h==0)return 0;
		int c[51][51]={},dp[51][51]={};
		rep(i,h)rep(j,w)cin>>c[j][i];

		int ans=0;
		rep(i,h){
			rep(j,w){
				if(c[j][i]==0||dp[j][i]==1)continue;
				ans++;
				queue<pos> que;
				pos pos1={j,i};
				que.push(pos1);
				dp[j][i]=1;
				while(!que.empty()){
					pos pos2=que.front();que.pop();
					if(dp[pos2.x+1][pos2.y]==0&&c[pos2.x+1][pos2.y]==1){
						pos pos3={pos2.x+1,pos2.y};
						dp[pos2.x+1][pos2.y]=1;
						que.push(pos3);
					}
					if(dp[pos2.x-1][pos2.y]==0&&c[pos2.x-1][pos2.y]==1){
						pos pos4={pos2.x-1,pos2.y};
						dp[pos2.x-1][pos2.y]=1;
						que.push(pos4);
					}
					if(dp[pos2.x][pos2.y+1]==0&&c[pos2.x][pos2.y+1]==1){
						pos pos5={pos2.x,pos2.y+1};
						dp[pos2.x][pos2.y+1]=1;
						que.push(pos5);
					}
					if(dp[pos2.x][pos2.y-1]==0&&c[pos2.x][pos2.y-1]==1){
						pos pos6={pos2.x,pos2.y-1};
						dp[pos2.x][pos2.y-1]=1;
						que.push(pos6);
					}
					if(dp[pos2.x+1][pos2.y-1]==0&&c[pos2.x+1][pos2.y-1]==1){
						pos pos7={pos2.x+1,pos2.y-1};
						dp[pos2.x+1][pos2.y-1]=1;
						que.push(pos7);
					}
					if(dp[pos2.x+1][pos2.y+1]==0&&c[pos2.x+1][pos2.y+1]==1){
						pos pos8={pos2.x+1,pos2.y+1};
						dp[pos2.x+1][pos2.y+1]=1;
						que.push(pos8);
					}
					if(dp[pos2.x-1][pos2.y+1]==0&&c[pos2.x-1][pos2.y+1]==1){
						pos pos9={pos2.x-1,pos2.y+1};
						dp[pos2.x-1][pos2.y+1]=1;
						que.push(pos9);
					}
					if(dp[pos2.x-1][pos2.y-1]==0&&c[pos2.x-1][pos2.y-1]==1){
						pos pos10={pos2.x-1,pos2.y-1};
						dp[pos2.x-1][pos2.y-1]=1;
						que.push(pos10);
					}
				}
			}
		}
		cout<<ans<<endl;
	}

	return 0;
}

C++: # include <iostream>

const int MAX_W = 50;
const int MAX_H = 50;

int w, h;

int c[MAX_H][MAX_W];

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

void dfs(int x, int y) {
	c[y][x] = 2;
	for (int i = 0; i < 8; ++i) {
		int nx = x + dx[i];
		int ny = y + dy[i];
		if (nx<0 || ny<0 || nx>w || ny>h)
			continue;
		if (c[ny][nx] == 1)
			dfs(nx, ny);
	}
}

int solve() {
	int sum = 0;
	for (int i = 0; i < h; ++i) {
		for (int j = 0; j < w; ++j) {
			if (c[i][j] == 1) {
				++sum;
				dfs(j, i);
			}
		}
	}
	return sum;
}

int main() {
	while (1) {
		std::cin >> w >> h;
		if ((w + h) == 0)
			break;
		for (int i = 0; i < h; ++i) {
			for (int j = 0; j < w; ++j)
				std::cin >> c[i][j];
		}
		int res = solve();
		std::cout << res << std::endl;
	}
	return 0;
}

C++: #include <stdio.h>

void solve(int a[50][50],int x,int y){
	int i, j;
	a[y][x] = 0;
	for(i = y - 1;i <= y + 1;i++){
		for(j = x - 1;j <= x + 1;j++)
			if(a[i][j] == 1) solve(a,j,i);
	}
}

int main(void){
	int w, h, i, j, flag[50][50], count;
	scanf("%d%d",&w,&h);
	while(w != 0 || h != 0){
		for(i = 0;i < h;i++)
			for(j = 0;j < w;j++) scanf("%d",&flag[i][j]);
		count = 0;
		for(i = 0;i < h;i++){
			for(j = 0;j < w;j++){
				if(flag[i][j]){
					count++;
					solve(flag,j,i);
				}
			}
		}
		printf("%d\n",count);
		scanf("%d%d",&w,&h);
	}
	return 0;
}

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

using namespace std;

int c[50][50];

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

int ret;

int w,h;

void dfs(int x,int y){
	if(c[x][y] == 0) return;
	c[x][y] = 0;
	for(int i=0;i<8;i++){
		if(x+dx[i] < 0 || x+dx[i] >= w) continue;
		if(y+dy[i] < 0 || y+dy[i] >= h) continue;
		dfs(x+dx[i],y+dy[i]);
	}
}

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