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>
#include<vector>
#include <queue>
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
#define rep2(i,a,b) for(int i=a;i<=b;i++)
#define pii pair<int,int>
int w,h;

int main(){
    while(1){
        w=h=0;
        cin>>w>>h;
        int ans=0;
        if(w==0&&h==0)break;
        vector<vector< int > > c(60,vector<int>(60));
        rep2(i,1,h)rep2(j,1,w){
            cin>>c[i][j];
        }
        vector< vector< int> > visited(60,vector<int>(60));
        rep2(i,1,h){
            rep2(j,1,w){
                if(visited[i][j]||!c[i][j])continue;
                queue<pii> q;
                q.push(pii(i,j));
                visited[i][j]=1;
                while(!q.empty()){
                    pii P=q.front();
                    //cout<<P.first<<" "<<P.second<<endl;
                    q.pop();
                    rep2(ii,-1,1){
                        rep2(jj,-1,1){
                            if(c[P.first+ii][P.second+jj]&&!visited[P.first+ii][P.second+jj]){
                                q.push(pii(P.first+ii,P.second+jj));
                                visited[P.first+ii][P.second+jj]=1;
                            }
                        }
                    }
                }
                if(c[i][j])ans++;
            }
        }
        cout<<ans<<endl;
    }

}

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

using namespace std;

pair<int, int> serch_land(vector<vector<int> >& maps){
  for(int i = 0; i < maps.size(); i++){
    for(int j = 0; j < maps[i].size(); j++){
      if(maps[i][j] == 1){
        return make_pair(i, j);
      }
    }
  }
  return make_pair(-1, -1);
}

void delete_land(vector<vector<int> >& maps, pair<int, int> start){
  int dh[8] = {1, 1, 1, 0, 0, -1, -1, -1};
  int dw[8] = {1, 0, -1, 1, -1, 1, -1, 0};

  stack< pair<int, int> > s;
  s.push(start);
  pair<int, int> cur;
  maps[start.first][start.second] = 0;

  while(!s.empty()){
    cur = s.top();
    s.pop();

    for(int i = 0; i < 8; i++){
      if(maps[cur.first + dh[i]][cur.second + dw[i]] == 1){
        maps[cur.first + dh[i]][cur.second + dw[i]] = 0;
        pair<int, int> next = make_pair(cur.first + dh[i], cur.second + dw[i]);
        s.push(next);
      }
    }
  }
}

int main(){
  int w, h;

  while(cin >> w >> h, !(w == 0 && h == 0)){
    vector<vector<int> > maps = vector<vector<int> >(h+2, vector<int>(w+2));
    pair<int, int> land;

    for(int i = 0; i < h+2; i++){
      for(int j = 0; j < w+2; j++){
        if(i == 0 || j == 0 || i == h+1 || j == w+1){
          maps[i][j] = 0;
        }else{
          cin >> maps[i][j];
        }
      }
    }


    int cnt = 0;
    while(land = serch_land(maps), land.first != -1){
      cnt++;
      delete_land(maps, land);
    }
    cout << cnt << endl;

  }
}

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

typedef long long LL;

//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define DECIM8  fixed<<setprecision(8) 
#define SZ(a) int((a).size())
#define SORT(c) sort((c).begin(),(c).end())

//repetition
//------------------------------------------
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

//constant
//--------------------------------------------
const double EPS = 1e-10;
const double PI  = acos(-1.0);

//clear memory
#define CLR(a) memset((a), 0 ,sizeof(a))

using namespace std;
int f[64][64];

int del(int i,int j)
{
  if(i<0||j<0) return 0;
  if(f[i][j]){
    f[i][j]=0;
    REP(di,3) REP(dj,3)
      del(i+di-1,j+dj-1);
    return 1;
  }
  else return 0;
}
int main(void)
{
  for(;;){
    int n,m;
    cin >> n >> m;
    if(!n&&!m) return 0;
    REP(j,m){
      REP(i,n)
	cin >> f[i][j];
    }
    int answer=0;
    REP(j,m){
      REP(i,n)
	answer+=del(i,j);
    }
    cout << answer << endl;
  }
}

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

int dx[] = {0, 0, 1, -1, 1, -1, 1, -1}, dy[] = {1, -1, 0, 0, 1, -1, -1, 1}, W, H;
bool mem[50][50];

int bfs(int sx, int sy)
{
  if(!mem[sy][sx])
    return 0;
  queue<int> q;
  q.push(sx);
  q.push(sy);
  while(!q.empty())
  {
    int x = q.front(); q.pop();
    int y = q.front(); q.pop();
    mem[y][x] = 0;
    for(int i = 0; i < 8; i++)
    {
      int tx = x + dx[i];
      int ty = y + dy[i];
      if(tx >= 0 && tx < W && ty >= 0 && ty < H && mem[ty][tx])
      {
        q.push(tx);
        q.push(ty);
      }
    }
  }
  return 1;
}

int main()
{
loop:
  int ans = 0;
  for(int y = 0; y < 50; y++)
    for(int x = 0; x < 50; x++)
      mem[y][x] = 0;
  cin >> W >> H;
  if(!W)
    return 0;
  for(int y = 0; y < H; y++)
    for(int x = 0; x < W; x++)
      cin >> mem[y][x];
  for(int y = 0; y < H; y++)
    for(int x = 0; x < W; x++)
      ans += bfs(x, y);
  cout << ans << endl;
  goto loop;
}

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

int H,W;
vector<vector<int> >field;

void dfs(int h, int w)
{
    field[h][w] = 0;
    
    for(int dh = -1; dh <= 1; dh++)
    {
        for(int dw = -1; dw <= 1; dw++)
        {
            int nh = h + dh;
            int nw = w + dw;
            
            if((nh >= H)||(nh < 0)||(nw >= W)||(nw < 0)) continue;
            if(field[nh][nw] == 0) continue;
            
            dfs(nh,nw);
        }
    }
}



int main()
{
    while(cin >> W >> H)
    {
        if((W == 0)||(H == 0)) break;
        field.assign(H,vector<int>(W,0));
        for(int h = 0; h < H; h++)
        {
            for(int w = 0; w < W; w++)
            {
                cin >> field[h][w];
            }
        }
        
        int count = 0;
        for(int h = 0; h < H; h++)
        {
            for(int w = 0; w < W; w++)
            {
                if(field[h][w] == 0) continue;
                dfs(h,w);
                count++;
            }
        }
        cout << count << endl;
    }
}

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

int m[51][51];
bool v[51][51];
int h,w;
int dx[8]={-1,-1,0,1,1,1,0,-1};
int dy[8]={0,-1,-1,-1,0,1,1,1};
void dfs(int x,int y){
    if(v[y][x])return;
    v[y][x]=1;
    for(int i=0;i<8;i++){
        int nx=x+dx[i];
        int ny=y+dy[i];
        if(nx>=0&&nx<w&&ny>=0&&ny<h&&!v[ny][nx]&&m[ny][nx]){
            dfs(nx,ny);
        }
    }
}
int main(){
    while(cin>>w>>h,h){
        int c=0;
        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                cin>>m[i][j];
                v[i][j]=0;
            }
        }
        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                if(!v[i][j]&&m[i][j]){
                    dfs(j,i);
                    c++;
                }
            }
        }
        cout<<c<<endl;
    }
}