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<algorithm>
using namespace std;
int H,W,k[100][100],n[100][100],color=1,i,j,l,m,o,r;
int main(){cin>>H>>W;for(i=0;i<H;i++){for(j=0;j<W;j++){cin>>k[i][j];}}
for(i=0;i<H;i++){for(j=0;j<W;j++){if(r==1){color++;}r=0;if(k[i][j]==1 && n[i][j]==0){n[i][j]=color;for(l=0;l<100;l++){
	for(m=0;m<H;m++){for(o=0;o<W;o++){if(n[m][o]==color){
		for(int p=-1;p<=1;p++){for(int q=-1;q<=1;q++){if(m-p>=0 && m-p<H){if(o-q>=0 && o-q<W){n[m][o]=color;}}}}
	}}}
}}}}
cout<<color<<endl;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<string>
#include<utility>
#include<map>
#include<set>
#include<queue>
using namespace std;
#define N (1000000000+7)
typedef pair<int,int> P;
typedef long long ll;

int h,w;
int board[60][60];
bool check(int i,int j){
    return (i>=1)&&(i<=h)&&(j>=1)&&(j<=w)&&(board[i][j]==1);
}

void dfs(int i,int j){
    if(check(i,j)){
        board[i][j]=-1;
        for(int x=i-1;x<=i+1;++x){
            for(int y=j-1;y<=j+1;++y){
                dfs(x,y);
            }
        }
    }
    else return;
}

int main(void){
    while(true){
        cin>>w>>h;
        int sx=0,sy=0;
        int ans=0;
        if((h==0)&&(w==0))break;
        for(int i=1;i<=h;i++){
            for(int j=1;j<=w;j++){
                cin>>board[i][j];
            }
        }
        for(int i=1;i<=h;i++){
            for(int j=1;j<=w;j++){
                if(board[i][j]==1){
                    dfs(i,j);
                    ans++;
                }
            }
        }
        cout<<ans<<endl;
    }

    return 0;
}

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

vector<int> xw = {-1,  0,  1, -1,  1, -1,  0,  1 };
vector<int> yh = {-1, -1, -1,  0,  0,  1,  1,  1 };
void dfs( vector<vector<int>> &vec, int X, int Y, int &w, int &h, vector<vector<bool>> &ck ){
  if ( ck.at(Y).at(X) ) return;
  
  ck.at(Y).at(X) = true;
  for (int i=0; i<8; i++) {
    int x = X + xw.at(i);
    int y = Y + yh.at(i);
    if( x < 0 || w <= x ) continue;
    if( y < 0 || h <= y ) continue;
    if ( vec.at(y).at(x) ) dfs( vec, x, y, w, h, ck);
  }
}

int main() {
  
  while (true) {
  int W,H;
  cin >> W >> H;
  if( W == 0 || H == 0) break;
    
  vector<vector<int>> P(H, vector<int>(W));
  for (int i=0; i<H; i++) {
    for (int j=0; j<W; j++) {
      cin >> P.at(i).at(j);  
    }
  }
  
  vector<vector<bool>> checked(H, vector<bool>(W, false));
  int res = 0;
  for (int h=0; h<H; h++) {
    for (int w=0; w<W; w++) {
      if( !checked.at(h).at(w) && P.at(h).at(w) ) {
         res++; dfs( P, w, h, W, H, checked);
      }
    }
  }
  
  cout << res << endl;
    
  }
  return 0;
}

C++: #include <iostream>
#include <cstdlib>
#include <queue>
#include <math.h>
#include <vector>
#include <algorithm>
#include <string>
#include <bitset>
using namespace std;

vector<vector<int>> c;
int w, h;

void search(int i, int j){
    if(i-1 >= 0 && j-1 >= 0 && c[i-1][j-1] == 1){
        c[i-1][j-1] = 0;
        search(i-1, j-1);
    }
    if(j-1 >= 0 && c[i][j-1] == 1){
        c[i][j-1] = 0;
        search(i, j-1);
    }
    if(i+1 < h && j-1 >= 0 && c[i+1][j-1] == 1){
        c[i+1][j-1] = 0;
        search(i+1, j-1);
    }
    if(i-1 >= 0 && c[i-1][j] == 1){
        c[i-1][j] = 0;
        search(i-1, j);
    }
    if(i+1 < h && c[i+1][j] == 1){
        c[i+1][j] = 0;
        search(i+1, j);
    }
    if(i-1 >= 0 && j+1 < w && c[i-1][j+1] == 1){
        c[i-1][j+1] = 0;
        search(i-1, j+1);
    }
    if(j+1 < w && c[i][j+1] == 1){
        c[i][j+1] = 0;
        search(i, j+1);
    }
    if(i+1 < h && j+1 < w && c[i+1][j+1] == 1){
        c[i+1][j+1] = 0;
        search(i+1, j+1);
    }
    return;
}

int main()
{
    int ans;
    while(true){
        cin >> w >> h;
        if(w == 0 && h == 0){
            break;
        }
        // init
        ans = 0;
        c.resize(h);
        for(int i=0; i<h; ++i){
            c[i].resize(w);
            for(int j=0; j<w; ++j){
                cin >> c[i][j];
            }
        }
        // search
        for(int i=0; i<h; ++i){
            for(int j=0; j<w; ++j){
                if(c[i][j] == 1){
                    ans++;
                    c[i][j] = 0;
                    search(i, j);
                }
            }
        }
        // output
        cout << ans << endl;
        // clear
        for(int i=0; i<h; ++i){
            c[i].clear();
        }
        c.clear();
    }
    return 0;
}

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

int field[50+2][50+2];
int dx[8]={0,1,1,1,0,-1,-1,-1};
int dy[8]={-1,-1,0,1,1,1,0,-1};

int rec(int x, int y)
{
  int i;

  if(field[x][y]!=1) return 0;
  field[x][y] = 0;
  for(i=0;i<8;i++) rec(x+dx[i],y+dy[i]);
  return 1;
}

int main()
{
  int w,h;
  int i,j;
  int n;
  while(cin>>w>>h,w|h){
    for(j=1;j<=h;j++)
      for(i=1;i<=w;i++)
	cin>>field[i][j];
    for(j=1;j<=h+1;j++)
      field[w+1][j]=0;
    for(i=1;i<=w+1;i++)
      field[i][h+1]=0;

    n = 0;
    for(j=1;j<=h;j++) for(i=1;i<=w;i++) n += rec(i,j);

    cout<<n<<endl;
  }
}

C++: #include <bits/stdc++.h>
using namespace std;
#define int long long
#define ll long long
#define fi first
#define se second
#define pb push_back
#define rep(i, s, n) for (int i = s; i < n; i++)
#define rrep(i, s, n) for (int i = (n)-1; i >= (s); i--)
#define all(a) a.begin(),a.end()
typedef pair<int,int>pint;
typedef vector<int>vint;
typedef vector<pint>vpint;
const long long MOD = 1000000007, INF = 1e17;
 
#define endl '\n'
#define IOS() ios_base::sync_with_stdio(0);cin.tie(0)
 
template<class T>inline bool chmax(T& a,T b){if(a<b){a=b;return true;}return false;}
template<class T>inline bool chmin(T& a,T b){if(a>b){a=b;return true;}return false;}

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

int a[55][55],H,W;

void dfs(int i,int j,vector<vector<int>>&used){
	used[i][j] = true;
	rep(k,0,8){
		int ni = i + dy[k],nj = j + dx[k];
		if(ni<0||nj<0||H<=ni||W<=nj)continue;
		if(a[ni][nj]==0)continue;
		if(used[ni][nj])continue;
		dfs(ni,nj,used);
	}
}

signed main()
{
	//IOS();
	vector<int>ans;
	while(1){
		cin>>W>>H;
		if(W==0&&H==0)break;
		for(int i = 0;i < H;i++){
			for(int j = 0;j < W;j++){
				cin>>a[i][j];
			}
		}
		vector<vector<int>>used(H,vector<int>(W,0));
		int cnt = 0;
		for(int i = 0;i < H;i++){
			for(int j = 0;j < W;j++){
				if(used[i][j])continue;
				if(a[i][j]==0)continue;
				dfs(i,j,used);
				cnt++;
			}
		}
		ans.push_back(cnt);
	}
	for(auto e:ans){
		cout<<e<<endl;
	}
}