Go: // AOJ 1160: How Many Islands? http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1160

package main

import (
	"bufio"
	"container/list"
	"fmt"
	"os"
	"strconv"
)

var SEA = 0
var LAND = 1

func nextInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

func discoverIslands(M, V [][]int, H, W int) int {
	// 島を探す
	queue := list.New()
	islands := 0
	for i := 1; i <= H; i++ {
		for j := 1; j <= W; j++ {
			// 訪問済みの土地ならスキップ
			if V[i][j] == 1 {
				continue
			}

			// 訪問中の土地が海なら訪問済みにしてスキップ
			if M[i][j] == SEA {
				V[i][j] = 1
				continue
			}

			// 未訪問の陸地が見つかったので
			// 島の数を1つ増やし、この陸地から辿れる陸地を訪問していく
			islands++
			queue.PushBack([]int{i, j})

			for queue.Len() > 0 {
				cur := queue.Remove(queue.Front()).([]int)
				h, w := cur[0], cur[1]
				if V[h][w] == 1 {
					continue
				}
				V[h][w] = 1

				// 全方向に未訪問の陸地がないか探索
				for v := -1; v <= 1; v++ {
					for l := -1; l <= 1; l++ {
						dh := h + v
						dw := w + l
						if M[dh][dw] == LAND && V[dh][dw] == 0 {
							queue.PushBack([]int{dh, dw})
						}
					}
				}
				/*
					if M[h-1][w] == LAND {
						queue.PushBack([]int{h - 1, w})
					}
					if M[h-1][w+1] == LAND {
						queue.PushBack([]int{h - 1, w + 1})
					}
					if M[h][w+1] == LAND {
						queue.PushBack([]int{h, w + 1})
					}
					if M[h+1][w+1] == LAND {
						queue.PushBack([]int{h + 1, w + 1})
					}
					if M[h+1][w] == LAND {
						queue.PushBack([]int{h + 1, w})
					}
					if M[h+1][w-1] == LAND {
						queue.PushBack([]int{h + 1, w - 1})
					}
					if M[h][w-1] == LAND {
						queue.PushBack([]int{h, w - 1})
					}
					if M[h-1][w-1] == LAND {
						queue.PushBack([]int{h - 1, w - 1})
					}
				*/
			}
		}
	}
	return islands
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	for {
		W, H := nextInt(sc), nextInt(sc)

		if W == 0 && H == 0 {
			break
		}
		// Initialize map and visted list
		M := make([][]int, H+2)
		V := make([][]int, H+2)
		for i := 0; i < H+2; i++ {
			M[i] = make([]int, W+2)
			V[i] = make([]int, W+2)
		}
		for i := 1; i <= H; i++ {
			for j := 1; j <= W; j++ {
				M[i][j] = nextInt(sc)
			}
		}

		islands := discoverIslands(M, V, H, W)

		fmt.Println(islands)
	}
}

C++: #include<iostream>
#include<vector>
using namespace std;
int needx[]={-1,0,1,0,1,1,-1,-1};
int needy[]={0,1,0,-1,1,-1,1,-1};
//テ・ツウツカテ」ツつ津・ツ?ィテ」ツ?ヲfalseテ」ツ?ォテ・ツ、ツ嘉」ツ?暗」ツ?ヲtrueテ」ツつ津ィツソツ氾」ツ?凖ゥツ鳴「テヲツ閉ー//
bool land(int x,int y,vector<vector<bool> >& cango){
    if(cango[x][y]){
        cango[x][y]=false;
        for(int i=0;i<8;i++){
            int nextx=x+needx[i];
            int nexty=y+needy[i];
            if(cango[nextx][nexty])
                bool flag=land(nextx,nexty,cango);
            }
    return true;
     }else{
return false;
    }
}
int main(void){
    int input;
	int w,h;
	while(1){
cin>>w>>h;
if(h==0)break;
    vector<vector<bool> > cango(h+2,vector<bool>(w+2,false));
    for(int i=1;i<=h;i++){
        for(int j=1;j<=w;j++){
            cin >>input;
            if(input==1){
cango[i][j]=true;
            }
        }
    }
  
    int t=0;
for(int i=1;i<=h;i++){
    for(int j=1;j<=w;j++){
        if(land(i,j,cango)){
            t++;
        }
    }
}
cout <<t<<endl;
	}
return 0;
}

C++: #include <iostream>
#include <queue>
#include <utility>

using namespace std;
using Point = pair<int,int>;

int map[52][52];

void BFS(const Point &p0){
  queue<Point> q;
  q.push(p0);
  map[p0.first][p0.second] = 0;
  while(!q.empty()){
    auto p = q.front();q.pop();
    int y = p.first , x = p.second;

    for(int i=-1;i<=1;++i){
      for(int j=-1;j<=1;++j){
        if(i==0&&j==0)continue;
        if(map[i+y][j+x]){
          q.push(Point(i+y,j+x));
          map[i+y][j+x] = 0;
        }
      }
    }

  }

}

int main(){
  int w,h;
  while(cin>>w>>h&&w>0&&h>0){

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


    int num = 0;
    for(int i=1;i<h+1;++i){
      for(int j=1;j<w+1;++j){
        if(map[i][j]){
          BFS(Point(i,j));
          num++;
        }
      }
    }
    cout << num << endl;
  }

  return 0;
}

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

#define rep(i,n) for(int i = 0; i < (n); i++)
#define rrep(i,n) for(int i = (n)-1; i >= 0; i--)
#define rep1(i,n) for(int i = 1; i <= (n); i++)
#define rrep1(i,n) for(int i = (n); i > 0; i--)

#define ll long long
#define pi pair<int, int>
#define pll pair<ll, ll>

#define MOD 1000000007
#define INF 1000000000000000LL

using namespace std;

#define MAX_LEN 50
int board[MAX_LEN][MAX_LEN];
bool used[MAX_LEN][MAX_LEN];
int w,h;

bool isin(int x, int y){
  return (x>=0 && x<w && y>=0 && y<h);
}

void dfs(int x, int y){
  if( !isin(x, y) )return;
  if(used[y][x])return;
  if(board[y][x]==0)return;
  used[y][x]=true;

  dfs(x-1, y);
  dfs(x+1, y);
  dfs(x, y-1);
  dfs(x, y+1);

  dfs(x-1, y-1);
  dfs(x-1, y+1);
  dfs(x+1, y-1);
  dfs(x+1, y+1);
}

int main(){
  while(true){
    cin>>w>>h;
    if(w==0 && h==0)break;
    rep(i, MAX_LEN)rep(j, MAX_LEN){
      board[i][j]=0;
      used[i][j]=false;
    }

    rep(i, h)rep(j, w)cin>>board[i][j];

    int result=0;
    rep(i, h)rep(j, w){
      if(board[i][j]==1 && !used[i][j])result++;
      dfs(j, i);
    }

    // rep(i, h){
    //   rep(j, w)cout<<board[i][j];
    //   cout<<endl;
    // }

    cout<<result<<endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll MOD = 1e9 + 7;
const ll INF = 1LL << 60;
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define debug(x) cerr << #x << ": " << x << endl;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}

ll c[100][100];
bool b[100][100];
ll dx[8] = {0, 0, 1, 1, 1, -1, -1, -1}, dy[8] = {1, -1, 0, 1, -1, 0, -1, 1};
ll w, h;

void dfs(ll x, ll y) {
    b[x][y] = true;
    rep(i, 8) {
        ll nx = x + dx[i], ny = y + dy[i];
        if (0 <= nx && nx < h && 0 <= ny && ny < w && c[nx][ny] == 1) {
            if (b[nx][ny]) continue;
            dfs(nx, ny);
        }
    }
}

int main() {
    vector<ll> vec;
    while(cin >> w >> h) {
        if(w == 0 && h == 0) {
            for(auto v : vec) cout << v << endl;
            return 0;
        }

        rep(i, h) rep(j, w) cin >> c[i][j];
        rep(i, h) rep(j, w) b[i][j] = false;

        ll ans = 0;
        rep(i, h) rep(j, w) {
            if (c[i][j] == 1 && b[i][j] == false) {
                ans++;
                dfs(i, j);
            }
        }
        vec.push_back(ans);
    }
}