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;

int w,h;
int m[50][50];

void solve(int x,int y){
	if(m[y][x] == 1){
		m[y][x] = 0;
		for(int i=-1;i<2;i++){
			for(int j=-1;j<2;j++){
				if(i==0&&j==0){
					continue;
				}
				if(y+i >= 0 && y+i < h && x+i >= 0 && x+i <= w){
					solve(x+j,y+i);
				}
			}
		}
	}
}

int main(){
	while(true){
		int count=0;

		cin >> w >> h;
		if(w==0&&h==0){
			break;
		}

		for(int i=0;i<h;i++){
			for(int j=0;j<w;j++){
				cin >> m[i][j];
			}
		}

		for(int i=0;i<h;i++){
			for(int j=0;j<w;j++){
				if(m[i][j] == 1){
					solve(j,i);
					count++;
				}
			}
		}

		cout << count << endl;
	}
}

C++: #include <bits/stdc++.h>
#include <math.h>
#include <vector>
#include <queue>
#include <iomanip>
#include <string>
#include <algorithm>
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
#define rep_1 (i,j,n) for(int i=j;i<n;i++)
typedef long long ll;
typedef long l;
const ll l_INF = 1010101010101010;
const int INF = 1010101010;
const int dx[] = {-1,0,1,0,-1,-1,1,1};
const int dy[] = {0,-1,0,1,1,-1,1,-1};
bool seen[100][100];
int w,h;
bool c[100][100];

int main(){
  while(true){
    cin>>w>>h;
    if(w==0) return 0;
    int cnt=0;
    rep(i,h)rep(j,w) seen[j][i]=false;
    rep(i,h)rep(j,w) cin>>c[j][i];
    int num=0;
    /*rep(i,h){
      rep(j,w) cout<<c[j][i];
      cout<<endl;
    }*/
    rep(i,h){
      rep(j,w){
        stack<int> q;
        if(c[j][i]==0||seen[j][i]) continue;
        q.push(i*w+j);
        while(!q.empty()){
          int x=q.top()%w,y=q.top()/w;
          q.pop();
          if(c[x][y]==0||seen[x][y]) continue;
          //cout<<x<<' '<<y<<endl;
          rep(d,8){
            if(y+dy[d]<0||y+dy[d]>=h||x+dx[d]<0||x+dx[d]>=w) continue;
            if(c[x+dx[d]][y+dy[d]]==0||seen[x+dx[d]][y+dy[d]]) continue;
            q.push((x+dx[d])+(y+dy[d])*w);
          }
          seen[x][y]=true;
        }
        num++;
        //cout<<i<<' '<<j<<endl;
      }
    }
    cout<<num<<endl;
  }
}

C++: #include<bits/stdc++.h>
#define rep(i,a,b) for(int i=int(a);i<int(b);++i)
using namespace std;
typedef long long ll;
int INF = (1LL << 30) - 1;
int MOD = 1e9+7;
int H,W;
void dfs(int h,int w,vector<vector<int> > table){
    //cout << h << " " << w << endl;
    table[h][w] = 0;
    int dx[] = {-1,-1,-1,0,0,1,1,1};
    int dy[] = {-1,0,1,-1,1,-1,0,1};
    rep(i,0,8){
        int nx = w + dx[i];
        int ny = h + dy[i];
        if (nx >= W || nx < 0 || ny >= H || ny < 0) continue;
        if(table[ny][nx])dfs(ny,nx,table);
    }
}
main(){
    cin >> H >> W;
    vector< vector<int> > table;
    while(H){
        table = vector< vector<int> > (H,vector<int>(W) );
        rep(i,0,H)rep(j,0,W)cin >> table[i][j];
        int cnt = 0;
        rep(i,0,H)rep(j,0,W){
            if(table[i][j] == 1){
                dfs(i,j,table);
                cnt++;
            }
        }
        cin >> H >> W;
    }
}

C++: #include<bits/stdc++.h>
using namespace std;
int a[50][50];
void calc(int i,int j){
  if(a[i][j]==1){
    a[i][j]=2;
    calc(i+1,j);
    calc(i,j+1);
    calc(i+1,j+1);
    calc(i+1,j-1);
    calc(i-1,j);
    calc(i,j-1);
    calc(i-1,j-1);
    calc(i-1,j+1);
  }
  else return;
}

int main(){
  while(1){
    int w,h;
    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];
      }
    }
    int count=0;
    for(int i=0;i<h;i++){
      for(int j=0;j<w;j++){
	if(a[i][j]==1){
	  count++;
	  calc(i,j);
	}
      }
    }
    cout<<count<<endl;
  }
  return 0;
}

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

using namespace std;

#define PAIR pair<int, int>

int main() {
	int w, h;
	while (cin >> w >> h, w != 0 && h != 0) {
		bool field[52][52] = {{false}};

		for (int i = 1; i <= h; i++) {
			for (int j = 1; j <= w; j++) {
				cin >> field[i][j];
			}
		}

		stack<PAIR> st;
		int island = 0;
		int dx[] = {0, 1, 1, 1, 0, -1, -1, -1};
		int dy[] = { -1, -1, 0, 1, 1, 1, 0, -1};

		for (int i = 1; i <= h; i++) {
			for (int j = 1; j <= w; j++) {
				if (field[i][j]) {
					st.push(PAIR(i, j));
					while (!st.empty()) {
						int x = st.top().first;
						int y = st.top().second;
						st.pop();
						field[x][y] = false;
						for (int k = 0; k < 8; k++) {
							int nextX = x + dx[k];
							int nextY = y + dy[k];
							if (field[nextX][nextY]) {
								st.push(PAIR(nextX, nextY));
							}
						}
					}
					island++;
				}
			}
		}
		cout << island << endl;
	}
}

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

char c[102][102];

int mx, my;

void dfs(int x, int y){
    if(x < 0 || y < 0 || x >= mx || y >= my){
        return;
    }
    if(c[x][y] == '0'){
        return;
    }
    c[x][y] = '0';
    dfs(x+1, y);
    dfs(x+1, y+2);
    dfs(x+1, y-2);
    dfs(x-1, y);
    dfs(x-1, y+2);
    dfs(x-1, y-2);
    dfs(x, y+2);
    dfs(x, y-2);
    return;
}

int main(){
    int W, H, cnt = 0;
    scanf("%d %d\n", &W, &H);
    while(W != 0 || H != 0){
        mx = H;
        my = 2 * W;
        for(int k = 0; k < H; k++){
            cin.getline(c[k], sizeof(c[k]));
        }
        for(int i = 0; i < H; i++){
            for(int j = 0; j < 2 * W; j++){
                if(c[i][j] == '1'){
                    cnt++;
                    dfs(i, j);
                }
            }
        }
        cout << cnt << endl;
        scanf("%d %d\n", &W, &H);
        cnt = 0;
    }
}

C++: #include <iostream>
#include <algorithm>
#include <queue>
#include <array>
using namespace std;
typedef pair<int,int> P;

const array<int,8> dx={0,1,0,-1,1,1,-1,-1};
const array<int,8> dy={1,0,-1,0,1,-1,-1,1};
const int W=50;
const int H=50;

char M[H+1][W+1];

inline bool in_M(const int y,const int x){
    return (y>=0 && y<H && x>=0 && x<W);
}

void bfs(const int sy,const int sx){
    queue<P> que;

    que.push(P(sy,sx));
    M[sy][sx]='0';

    while(!que.empty()){
        P p=que.front();que.pop();

        for(int i=0;i<dx.size();i++){
            int ddy=p.first+dy[i],ddx=p.second+dx[i];
            if(in_M(ddy,ddx) && M[ddy][ddx]=='1'){
                que.push(P(ddy,ddx));
                M[ddy][ddx]='0';
            }
        }
    }
}

void solve(){
    int sum;
    int w,h;

    while(cin>>w>>h,w|h){
        cin.ignore();
        sum=0;

        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                cin>>M[i][j];
                cin.ignore();
            }
        }

        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                if(M[i][j]=='1'){
                    bfs(i,j);
                    sum++;
                }
            }
        }

        cout<<sum<<endl;
    }
}

int main(){
    solve();
    return 0;
}