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;

void exploreIsland( bool c[50][50], int h, int w, int y, int x )
{
    c[y][x] = 0;

    if( y - 1 >= 0 && c[y-1][x] == 1 )
        exploreIsland( c, h, w, y - 1, x ); 
    if( x - 1 >= 0 && y - 1 >= 0 && c[y-1][x-1] == 1 )
        exploreIsland( c, h, w, y - 1, x - 1 ); 
    if( x + 1 < w && y - 1 >= 0 && c[y-1][x+1] == 1 )
        exploreIsland( c, h, w, y - 1, x + 1 );
    if( x - 1 >= 0 && c[y][x-1] == 1 )
        exploreIsland( c, h, w, y, x - 1 ); 
    if( x + 1 < w && c[y][x+1] == 1 )
        exploreIsland( c, h, w, y, x + 1 );
    if( y + 1 < h && c[y+1][x] == 1 )
        exploreIsland( c, h, w, y + 1, x ); 
    if( x - 1 >= 0 && y + 1 < h && c[y+1][x-1] == 1 )
        exploreIsland( c, h, w, y + 1, x - 1 ); 
    if( x + 1 < w && y + 1 < h && c[y+1][x+1] == 1 )
        exploreIsland( c, h, w, y + 1, x + 1 ); 
}

int main()
{
    int h, w;
    bool c[50][50];

    while( cin >> w >> h )
    {
        if( h == 0 && w == 0 )
            break;
        
        for( int i = 0; i < h; i++ )
            for( int j = 0; j < w; j++ )
                cin >> c[i][j];
    
        int cnt = 0;
        for( int i = 0; i < h; i++ )
            for( int j = 0; j < w; j++ )
                if( c[i][j] == 1 )
                {
                    exploreIsland( c, h, w, i, j );
                    cnt++;
                }
        cout << cnt << endl;
    }
    return 0;
}

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

int w, h;
int field[60][60];

void dfs(int x, int y) {
  field[y][x] = 0;
  for(int i = -1; i <= 1; i++) {
    for(int j = -1; j <= 1; j++) {
      int tx = x+j, ty = y+i;
      if(0 <= tx && tx < w && 0 <= ty && ty < h && field[ty][tx] == 1) dfs(tx, ty);
    }
  }
}

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

    int ans = 0;
    for(int i = 0; i < h; i++) {
      for(int j = 0; j < w; j++) {
	if(field[i][j]) {
	  ans++;
	  dfs(j, i);
	}
      }
    }
    cout << ans << endl;
  }
}

C++: #include<iostream>
#include<cmath>
#include<algorithm>
#include<string>
#include<vector>
#include<stack>
#include<queue>
#include<set>
#include<map>
#include<iomanip>
#include<bitset>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> P;
typedef pair<ll,P> P1;
typedef pair<P,P> P2;
#define pu push
#define pb push_back
#define mp make_pair
#define eps 1e-7
#define INF 1000000000
#define fi first
#define sc second
#define rep(i,x) for(ll i=0;i<x;i++)
#define repn(i,x) for(ll i=1;i<=x;i++)
#define SORT(x) sort(x.begin(),x.end())
#define ERASE(x) x.erase(unique(x.begin(),x.end()),x.end())
#define POSL(x,v) (lower_bound(x.begin(),x.end(),v)-x.begin())
#define POSU(x,v) (upper_bound(x.begin(),x.end(),v)-x.begin())

const int MAX = 510000;
const int MOD = 1000000007;

// 四方向への移動ベクトル
const int dx[8] = {1, 0, -1, 0, 1, 1, -1, -1};
const int dy[8] = {0, 1, 0, -1, 1, -1, 1, -1};

// 入力
int H, W;
vector<vector<ll> > field;

// 探索
bool seen[51][51]; // seen[h][w] := マス (h, w) が検知済みかどうか
void dfs(int h, int w) {
    seen[h][w] = true;

    // 四方向を探索
    for (int dir = 0; dir < 8; ++dir) {
        int nh = h + dx[dir];
        int nw = w + dy[dir];

        // 場外アウトしたり、移動先が壁の場合はスルー
        if (nh < 0 || nh >= H || nw < 0 || nw >= W) continue;
        if (field[nh][nw] == 0) continue;

        // 移動先が探索済みの場合
        if (seen[nh][nw]) continue;

        // 再帰的に探索
        dfs(nh, nw);
    }
}

int main(){
  vector<ll> ans;
  while(1){
    cin >> W >> H;
    if(H == 0 and W == 0) break;
    field.clear();
    field.resize(H); rep(j,H) field[j].resize(W);
    rep(i,H) rep(j,W) cin >> field[i][j];

    rep(i,51) rep(j,51) seen[i][j] = false;
    ll tmp = 0;
    rep(i,H){
      rep(j,W){
        if(field[i][j] == 1 and seen[i][j] == false){
          dfs(i,j);
          tmp++;
        }
      }
    }
    ans.pb(tmp);
  }
  rep(i,ans.size()) cout << ans[i] << endl;
}

C++: //41
#include<iostream>

using namespace std;

int w,h;
bool imap[50][50];

void ff(int y,int x){
  imap[y][x]=false;
  for(int i=-1;i<=1;i++){
    for(int j=-1;j<=1;j++){
      int ny=y+i,nx=x+j;
      if(0<=ny&&ny<h&&0<=nx&&nx<w&&imap[ny][nx]){
	ff(ny,nx);
      }
    }
  }
}

int main(){
  for(;cin>>w>>h,w|h;){
    fill_n(&imap[0][0],50*50,false);
    for(int y=0;y<h;y++){
      for(int x=0;x<w;x++){
	cin>>imap[y][x];
      }
    }
    int ans=0;
    for(int y=0;y<h;y++){
      for(int x=0;x<w;x++){
	if(imap[y][x]){
	  ans++;
	  ff(y,x);
	}
      }
    }
    cout<<ans<<endl;
  }
  return 0;
}

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

#define REP(i,n,m) for(int i=n;i<m;i++)
#define rep(i,n) REP(i,0,n)

class Point{
public:
	int x,y;

	Point(int tx,int ty){
		x = tx;
		y = ty;
	}
};

int w,h;
int t[52][52];
int dx[] = {-1,0,1,-1,1,-1,0,1};
int dy[] = {-1,-1,-1,0,0,1,1,1};

int solve(void){
	int res = 0;

	rep(i,h) rep(j,w) if(t[i][j] == 1) {
		res++;
		deque<Point> stack;
		stack.push_back(Point(j,i));

		while(!stack.empty()){
			Point p = stack.back(); stack.pop_back();
			t[p.y][p.x] = 0;

			rep(k,8){
				int nx = p.x + dx[k];
				int ny = p.y + dy[k];

				if(nx>=0 && nx<w && ny>=0 && ny<h && t[ny][nx]==1){
					stack.push_back(Point(nx,ny));
				}
			}
		}
	}

	return res;
}

int main(void){
	while(cin>>w>>h && (w||h)){
		rep(i,h) rep(j,w) cin>>t[i][j];
		cout<<solve()<<endl;
	}


	return 0;
}