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>

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

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

int main(void){
  while(1){
    int cnt = 0;
    std::cin >> w >> h;
    if(w == 0 && h == 0)  return 0;
    for(int i=0; i < h; i++){
      for(int j=0; j < w; j++){
        std::cin >> map[i][j];
      }
    }

    for(int i=0; i < h; i++){
      for(int j=0; j < w; j++){
        if(map[i][j] == 1){
          cnt++;
          dfs(i, j);
        }
      }
    }

    std::cout << cnt << std::endl;

  }
}

C++: #include<bits/stdc++.h>
using namespace std;
#define inf 1e9
#define ll long long
#define ull unsigned long long
#define M 1000000007
#define P pair<int,int>
#define PLL pair<ll,ll>
#define FOR(i,m,n) for(int i=m;i<n;i++)
#define RFOR(i,m,n) for(int i=m;i>=n;i--)
#define rep(i,n) FOR(i,0,n)
#define rrep(i,n) RFOR(i,n,0)
#define all(a) a.begin(),a.end()
const int vx[4] = {0,1,0,-1};
const int vy[4] = {1,0,-1,0};
#define PI 3.14159265


void f(int w,int h){
  int map[100][100]={};
  bool c[100][100]={};

  rep(i,h){
    rep(j,w){
      cin>>map[i][j];
    }
  }

  int ans=0;
  rep(i,h){
    rep(j,w){
      if(map[i][j]&&!c[i][j]){
        
        queue<P> q;
        q.push(P(i,j));
        while(q.size()){
          P p=q.front(); q.pop();
          int a=p.first,b=p.second;
          for(int k=-1;k<2;k++){
            for(int l=-1;l<2;l++){
              int y=a+k;
              int x=b+l;
              if(0<=x&&x<w&&0<=y&&y<h)
              if(map[y][x]&&!c[y][x]){
                c[y][x]=true;
                q.push(P(y,x));
              }
            }
          }
        }
        ans++;
      }
    }
  }

  cout<<ans<<endl;
}

int main(){
  int w,h;
  while(1){
    cin>>w>>h;
    if(w==0) break;
    f(w,h);
  }

  return 0;
}

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

//int Flag=0;

void find_island(int *cp){
//	int length=cp-c1;

	*cp=0;
	
	if(*(cp+1)==1) find_island(cp+1);
	if(*(cp+52)==1)find_island(cp+52);
	if(*(cp+53)==1)find_island(cp+53);
	if(*(cp-1)==1)find_island(cp-1);
	if(*(cp-51)==1)find_island(cp-51);
	if(*(cp-52)==1)find_island(cp-52);
	if(*(cp-53)==1)find_island(cp-53);
	if(*(cp+51)==1)find_island(cp+51);	
}


int main()
{
	int w,h;

	cin>>w>>h;
	while( w!=0 || h!=0 ){
		int c[52][52]={},island=0;
		for(int i=1;i<=h;i++){
			for(int j=1;j<=w;j++){
				cin>>c[i][j];
			}
		}

		for(int i=1;i<=h;i++){
			for(int j=1;j<=w;j++){
				if(c[i][j]==1){
					island++;
					find_island(&c[i][j]);
				}
			}
		}
		cout<<island<<endl;
		cin>>w>>h;
	}
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll=long long;
typedef pair<int,int> P;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
int w,h;
int nx,ny;
vector<vector<int>>G;
void dfs(int a,int b){
     if(0>nx|| nx>=h || 0>ny|| ny>=w) return ;
     if( G.at(nx).at(ny)==0) return ; 
     G.at(a).at(b)=0;
    for(int k=-1;k<=1;k++){
        for(int s=-1;s<=1;s++){
            nx=a+k;
            ny=b+s;
            dfs(nx,ny);
        }
    }
}
 
 
 
int main(){
    cin>>w>>h;
    G.resize(h,vector<int>(w));
    for(int i=0;i<h;i++){
        for(int j=0;j<w;j++){
            cin>>G.at(i).at(j);
        }
    }
    int count=0;
    for(int i=0;i<h;i++){
        for(int j=0;j<w;j++){
            if(G.at(i).at(j)==1){
                count++;
                dfs(i,j);
            }
        }
    }
cout<<count<<endl;
}

C++: #include <iostream>

#define REP(i,n) for(int i=0; i<n; i++)
#define debug(x) cerr << #x << " = " << (x) << endl;

using namespace std;

int w, h, map[51][51], diff[9]={-1, 0, 1, 0, -1, 1, 1, -1, -1};

bool check(int j, int k){
	return (j>=0 && j<h && k>=0 && k<w && map[j][k]>0);
}

void dfs(int j, int k){
	REP(i,8){
		if (check(j+diff[i], k+diff[i+1])){
			map[j+diff[i]][k+diff[i+1]] = 0;
			dfs(j+diff[i],k+diff[i+1]);
		}
	}
	return;
}

int main(){
	while(1){
		int ans=0;
		cin >> w >> h;
		if (w==0 && h==0) break;
		REP(j,h){
			REP(k,w) map[j][k] = 0;
		}
		REP(j,h){
			REP(k,w) cin >> map[j][k];
		}
		REP(j,h){
			REP(k,w){
				if (check(j,k)){
					ans++;
					dfs(j,k);
				}
			}
		}
		cout << ans << endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define all(c) (c).begin(),(c).end()
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;i--)
#define REP(i,m,n) for(int i=(int)(m);i<(int)(n);i++)
#define rep(i,n) REP(i,0,n)
#define iter(c) __typeof((c).begin())
#define tr(it,c) for(iter(c) it=(c).begin();it!=(c).end();it++)
#define pb(a) push_back(a)
#define pr(a) cout<<(a)<<endl
#define PR(a,b) cout<<(a)<<" "<<(b)<<endl
#define F first
#define S second
#define ll long long
bool check(int n,int m,int x,int y){return (x<0||x>=n||y<0||y>=m)?false:true;}
const ll MAX=1000000007,MAXL=1LL<<60,dx[4]={-1,0,1,0},dy[4]={0,-1,0,1};
typedef pair<int,int> P;

int n,m;
int a[51][51];
bool d[51][51];

void dfs(int nx, int ny) {
  d[nx][ny]=true;
  REP(i,-1,2) {
    REP(j,-1,2) {
      int x=nx+i,y=ny+j;
      if(check(n,m,x,y) && a[x][y] && !d[x][y]) dfs(x,y);
    }
  }
}

int main() {
  while(cin >> m >> n && (n||m)) {
    rep(i,n) {
      rep(j,m) cin >> a[i][j];
    }
    memset(d,false,sizeof(d));
    int cnt=0;
    rep(i,n) {
      rep(j,m) {
	if(!d[i][j] && a[i][j]) {
	  cnt++;
	  dfs(i,j);
	}
      }
    }
    pr(cnt);
  }
  return 0;
}