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 c[60][60];
bool visited[60][60];
int dx[8] = {0, 1, 1, 1, 0, -1, -1, -1};
int dy[8] = {1, 1, 0, -1, -1, -1, 0, 1};
int h, w;

bool check(int x, int y){
  if(x < 0 || y < 0)return false;
  if(x >= w || y >= h)return false;
  if(visited[y][x])return false;
  if(c[y][x] == 0)return false;
  return true;
}

void dfs(int x, int y){ 
  if(!check(x, y))return;

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

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

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

    int cnt = 0;
    for(int i = 0; i < h; i++){
      for(int j = 0; j < w; j++){
        if(!visited[i][j] && c[i][j] == 1){
          dfs(j, i);
          cnt++;
        }
      }
    }
    cout << cnt << endl;
  }
}

C++: #include <iostream>

using namespace std;

#define WH 52

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

void dfs(int,int);

int main(int argc, char const *argv[])
{
	int w,h;


	int cnt;

	while(1){
		cin>>w>>h;
		if(w+h==0) break;

		for(int i1=0;i1<WH;i1++){
			for(int i2=0;i2<WH;i2++){
				f[i1][i2]=0;
			}
		}

		for(int i1=1;i1<=h;i1++){
			for(int i2=1;i2<=w;i2++){
				cin>>f[i1][i2];
			}
		}

		cnt=0;
		for(int i1=1;i1<=h;i1++){
			for(int i2=1;i2<=w;i2++){
				if(f[i1][i2]==1){
					f[i1][i2]=0;
					dfs(i2,i1);
					cnt++;
				}
			}
		}

		cout<<cnt<<endl;

	}

	return 0;
}

void dfs(int x,int y){
	for(int i1=0;i1<8;i1++){
		for(int i2=0;i2<8;i2++){
			if(f[y+dy[i1]][x+dx[i2]]==1){
				f[y+dy[i1]][x+dx[i2]]=0;
				dfs(x+dx[i2],y+dy[i1]);
			}
		}
	}
}

C++: #include <iostream>
#include <cmath>
#include <vector>
using namespace std;
int draw ( int width, int height,std::vector<std::vector<int>> map){
	for(int i =0; i < height; i ++){
		for(int j = 0; j < width; j ++){
			cout << map[j][i] << " ";
		}
		cout << endl;

	}
	return 0;
}
//未探索陸地か
bool judge (int width,int height,std::vector<std::vector<int>> map, int x, int y){
	if( x >=0 && x  < width && y >= 0 && y < height && map[x][y] == 1){
		return true;
	}
	return false;
}
//周辺を探査して塗りつぶす
std::vector<std::vector<int>> Conqure (int width,int height,std::vector<std::vector<int>> map, int x, int y, int color) {
	map[x][y] = color;
	for(int dx = -1; dx <= 1; dx++){
		for(int dy = -1; dy <= 1; dy++){
			if(judge(width,height,map,x+dx,y+dy)){
				map[x+dx][y+dy] = color;
				if(!(dx == 0 && dy == 0)){
					map = Conqure(width,height,map,x+dx,y+dy,color);
				}
				
			}
		}
	}
	return map;
}
int main () {
	while(true){
			int w,h;
	cin >> w >> h;
	if(w == 0 && h == 0){
		break;
	}
	std::vector<std::vector<int>> map;
		map.resize(w);		// ()内の数字が要素数になる
	for( int i=0; i<w; i++ ){
		map[i].resize(h);
	}
	int landCount = 0;
	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(judge(w,h,map,j,i)){
				landCount += 1;
				map = Conqure(w,h,map,j,i,landCount + 1);
				//draw(w,h,map);
			}
		}
	}
	cout <<  landCount << endl;
	}

}

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

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

int mesh[50][50];
int n, m;

struct Point
{
	int x;
	int y;
};

int main()
{
	deque<Point> stack;
	while (true)
	{
		scanf("%d %d", &n, &m);
		if (n == 0 && m == 0) break;
		for (int i = 0; i < n; i++)
		{
			for (int j = 0; j < m; j++)
			{
				int a;
				scanf("%d", &a);
				mesh[i][j] = a;
			}
		}
		int count = 0;
		for (int i = 0; i < n; i++)
		{
			for (int j = 0; j < m; j++)
			{
				if (mesh[i][j] == 1)
				{
					Point pt = {j, i};
					stack.push_front(pt);
					mesh[i][j] = 0;
					while (!stack.empty())
					{
						Point point = stack.front();
						stack.pop_front();
						for (int k = 0; k < 8; k++)
						{
							if (mesh[point.y+dy[k]][point.x+dx[k]] == 1)
							{
								Point pt = {j + dx[k], i + dy[k]};
								stack.push_front(pt);
								mesh[point.y+dy[k]][point.x+dx[k]] = 0;
							}
						}
					}
					count++;
				}
			}
		}
		printf("%d\n", count);
	}
}

C++: #include <bits/stdc++.h>
#define rep(i, a, b) for(int i = a; i < b; i++)
#define Rep(i, a, b) for(int i = a; i <= b; i++)
#define _GLIBCXX_DEBUG
#define Vl vector<ll>
#define Vs vector<string>
#define Vp vector<pair<ll, ll>>
#define ll long long
#define ALL(v) (v).begin(),(v).end()
using namespace std;
const double pi = acos(-1.0);
const ll MOD = 1e9 + 7;
const ll INF = 1LL << 60;

ll H, W;
bool c[100][100];
bool seen[510][510];
const int dx[8] = {0, 0, -1, 1, -1, 1, 1, -1};
const int dy[8] = {1, -1, 0, 0, 1, 1, -1, -1}; 

void dfs(ll h, ll w){
    seen[h][w] = true;

    ll nh, nw;
    rep(i, 0, 8){
        nh = h + dy[i];
        nw = w + dx[i];

        if(nh < 0 || nh >= H || nw < 0 || nw >= W) continue;
        if(seen[nh][nw]) continue;

        if(c[nh][nw]) dfs(nh, nw);
    }
}

void solve() {
    while(cin >> W >> H){
        if(W == 0 && H == 0) break;

        rep(h, 0, H) rep(w, 0, W) cin >> c[h][w];
        rep(h, 0, H) rep(w, 0, W) seen[h][w] = 0;

        ll ans = 0;
        rep(h, 0, H) rep(w, 0, W) { 
            if(c[h][w] && !(seen[h][w])){
                dfs(h, w);
                ans++;
            }
        }
        
        cout << ans << endl;
    }

    return;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    solve();
    return 0;
}