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 <bits/stdc++.h>
#include <math.h>
#define ALL(a)    a.begin(), a.end()
using namespace std;

vector<vector<int>> V;
vector<int> dx{0, 0, 1, 1, 1, -1, -1, -1};
vector<int> dy{1, -1, 0, 1, -1, 0, 1, -1};
vector<vector<bool>> seen;
int W = 1, H = 1, Ans = 0;


void dfs(int y, int x){
seen[y][x] = 1;

for(int i = 0; i < 8; i++){
int ny = y + dy[i], nx = x + dx[i];

if(ny < 0 || ny >= H || nx < 0 || nx >= W)continue;

if(V[ny][nx] == 0)continue;

if(seen[ny][nx])continue;

dfs(ny, nx);
}



}


int main() {


while(1){

cin >> W >> H;
if(H == 0 && W == 0)break;

V.resize(H);
seen.resize(H);

for(int i = 0; i < H; i++){
V[i].resize(W);seen[i].resize(W);}

for(int i = 0; i < H; i++){
for(int j = 0; j < W; j++){
cin >> V[i][j];
//cout << V.at(i).at(j);
seen[i][j] = 0;
}}

for(int i = 0; i < H; i++){
for(int j = 0; j < W; j++){
if(V[i][j] == 1 && seen[i][j] == 0){dfs(i, j);Ans++;}
}}
cout << Ans << endl;
Ans = 0;
}


}

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

using namespace std;

long long inf=1000000007;
long long h,w;

void dfs(long long y,long long x,vector<vector<bool>> &seen,vector<vector<long long>> grid){
	vector<long long> dy={1,1,1,0,0,-1,-1,-1};
	vector<long long> dx={1,0,-1,1,-1,1,0,-1};

	for(long long i=0;i<8;i++){
		long long py=y+dy.at(i);
		long long px=x+dx.at(i);

		if(py<0 || py>=h || px<0 || px>=w || grid.at(py).at(px)==0 || seen.at(py).at(px)) continue;

		seen.at(py).at(px)=true;
		dfs(py,px,seen,grid);
	}
}

int main(){
	cin>>w>>h;

	while(h!=0 || w!=0){
		vector<vector<long long>> grid(h,vector<long long>(w));
		for(long long i=0;i<h;i++){
			for(long long j=0;j<w;j++){
				cin>>grid.at(i).at(j);
			}
		}

		vector<vector<bool>> seen(h,vector<bool>(w,false));
		long long ans=0;

		for(long long i=0;i<h;i++){
			for(long long j=0;j<w;j++){
				if(grid.at(i).at(j)==0 || seen.at(i).at(j)) continue;
				ans++;
				seen.at(i).at(j)=true;
				dfs(i,j,seen,grid);
			}
		}

		cout<<ans<<endl;
		cin>>w>>h;
	}

	return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <map>
#include <cmath>
#include <string>
#include <sstream>
#include <iomanip>
#include <complex>
using namespace std;
 
#define ll long long
#define vvi vector< vector<int> >
#define All(X) X.begin(),X.end()
#define FOR(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define REP(i,n) for(int i=0;i<(int)(n);i++)
#define pb push_back 
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
ll lcm(ll a,ll b){return a/gcd(a,b)*b;}

int w,h;
int c[100][100];
bool notsearched[100][100];
int dx[8]={0,1,0,-1,1,1,-1,-1};
int dy[8]={1,0,-1,0,1,-1,1,-1};
int ans;

bool inrange(int x, int y){
  if(x<0||y<0||x>=h||y>=w){ 
	//cout << "false" <<endl;
	return false;
  }else{ 
	//cout << "true" << endl;
	return true;
  }
}

void search(int x, int y){

  if((notsearched[x][y])&&(c[x][y] == 1)&&(inrange(x,y))){
	notsearched[x][y]=false;

	REP(i,8) search(x+dx[i],y+dy[i]);
  }
}


int main(){
  while(1){

	REP(i,100){
	  REP(j,100){
		notsearched[i][j]=true;
	  }
	}

	cin >> w >> h;
	if (w==0&&h==0) break;
	ans=0;
	REP(i,h){
	  REP(j,w){
		cin >> c[i][j];

	  }
	}

	REP(i,h){
	  REP(j,w){
		if((notsearched[i][j])&&(c[i][j] == 1)&&(inrange(i,j))) ans++; 
		search(i,j);
	  }
	}
	cout << ans << endl;
  }
 
}

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

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

void dfs(int x, int y) {
  c[x][y] = 0;
  for (int dx = -1; dx <= 1; dx++) {
    for (int dy = -1; dy <= 1; dy++) {
      int nx = x + dx, ny = y + dy;
      if (0 <= nx && nx < h && 0 <= ny && ny < w && c[nx][ny] == 1)
        dfs(nx, ny);
    }
  }
  return;
}

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

C++: #include<iostream>
#include<iomanip>
#include<algorithm>
#include<cstdio>
#include<cmath>
#include<map>
#include<numeric>
#include<set>
#include<string>
#include<utility>
#include<vector>
#include<queue>


#define rep(i, a, n)  for(int i=a; i<n; i++)
#define per(i, a, n)  for(int i=n-1; i>=a; i--)
#define fill0(n)  setfill('0') << right << setw(n)
#define all(x)  (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define MAX 1000001
using namespace std;
typedef long long ll;

int w,h;
int c[51][51];

void dfs(int y,int x){
  if(y<1||51<=y||x<1||51<=x||c[y][x]==0)return;
  c[y][x]=0;
  dfs(y-1, x-1);
  dfs(y-1, x);
  dfs(y-1, x+1);
  dfs(y, x-1);
  dfs(y, x+1);
  dfs(y+1, x-1);
  dfs(y+1, x);
  dfs(y+1, x+1);
}

int main(){
  while(true){
    std::cin >> w>>h;
    if(w==0&&h==0)break;
    rep(i,1,h+1){
      rep(j,1,w+1){
        std::cin >> c[i][j];
      }
    }
    int res=0;
    rep(i,1,h+1){
      rep(j,1,w+1){
        // std::cout << c[1][1] << '\n';
        if(c[i][j]==1){
          // std::cout << "/* message */" << '\n';
          dfs(i,j);
          res++;
        }
      }
    }
    std::cout << res << '\n';
  }
  return 0;
}