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)
	}
}

Python: import sys

sys.setrecursionlimit(10**5)

def solve():
    while 1:
        w, h = map(int, sys.stdin.readline().split())

        if w == h == 0:
            return

        room = [[int(j) for j in sys.stdin.readline().split()] for i in range(h)]

        cnt = 0

        for i in range(h):
            for j in range(w):
                if room[i][j]:
                    cnt += 1
                    dfs(w, h, room, i, j)

        print(cnt)

def dfs(w, h, room, i, j):
    if i < 0 or i >= h or j < 0 or j >= w or (not room[i][j]):
        return

    room[i][j] = 0

    dfs(w, h, room, i + 1, j)
    dfs(w, h, room, i - 1, j)
    dfs(w, h, room, i, j + 1)
    dfs(w, h, room, i, j - 1)
    dfs(w, h, room, i + 1, j + 1)
    dfs(w, h, room, i + 1, j - 1)
    dfs(w, h, room, i - 1, j + 1)
    dfs(w, h, room, i - 1, j - 1)

if __name__ == '__main__':
    solve()

C++: #include <bits/stdc++.h>
using namespace std;
int ans = 1e9;
int H,W;
int mp[50][50];
int nx,ny;
void func(int y,int x){
	//cout << y << ' ' <<x<<endl;
	if(mp[y][x] == 1){
		mp[y][x] = 2;
		func(y,x);
	}
	if(mp[y+1][x] == 1){
		mp[y+1][x] = 2;
		func(y+1,x);
	}
	if(mp[y][x+1] == 1){
		mp[y][x+1] = 2;
		func(y,x+1);
	}
	if(mp[y+1][x+1] == 1){
		mp[y+1][x+1] = 2;
		func(y+1,x+1);
	}
	if(mp[y-1][x] == 1){
		mp[y-1][x] = 2;
		func(y-1,x);
	}
	if(mp[y][x-1] == 1){
		mp[y][x-1] = 2;
		func(y,x-1);
	}
	if(mp[y-1][x-1] == 1){
		mp[y-1][x-1] = 2;
		func(y-1,x-1);
	}
	if(mp[y+1][x-1] == 1){
		mp[y+1][x-1] = 2;
		func(y+1,x-1);
	}
	if(mp[y-1][x+1] == 1){
		mp[y-1][x+1] = 2;
		func(y-1,x+1);
	}
}
void findL(){
	nx = -1;ny = -1;
	for(int i = 0; i < H; i++){
		for(int j = 0; j < W; j++){
			if(mp[i][j] == 1){
				nx = j,ny = i;
				//cout <<nx<<ny<<endl;
				i = H; j = W;
			}
		}
	}
}
int main(){
	
	cin >> H>>W;
	while(W!=0){
		for(int i = 0; i < H; i++){
			for(int j = 0; j < W; j++){
				cin >> mp[i][j];
			}
		}
		int c = 0;
		findL();
		while(nx != -1 && ny != -1){
			func(ny,nx);
			c++;
			findL();
		}
		cout << c << endl;
		cin >> W >> H;
	}
	return 0;
}

C++: #include <stdio.h>
#include <algorithm>
#include <vector>
#include <queue>
#include <memory.h>
#include <functional>

using namespace std;

//FILE * in = freopen("B", "r", stdin);

typedef pair<int,int> P;

int n, m;
int cnt = 0;
int data[100][100];
int check[100][100];

int mvx[] = {-1, 0, 1, -1, 1, -1, 0, 1};
int mvy[] = {-1, -1, -1, 0, 0, 1, 1, 1};

void input() {
	for(int i = 0; i < m; i++){
		for(int j = 0; j < n; j++) {
			scanf("%d", &data[i][j]);
		}
	}
	cnt = 0;
	memset(check, 0, sizeof(check));
}

void bfs(int x, int y) {
	queue<P> que;
	que.push(P(x,y));
	check[x][y] = 1;
	while(!que.empty()){
		P cur = que.front(); que.pop();
		for(int i = 0; i < 8; i++) {
			if(cur.first + mvx[i] >= 0 && cur.first + mvx[i] < n && cur.second + mvy[i] >= 0 && cur.second + mvy[i] < m
				&& data[cur.first + mvx[i]][cur.second + mvy[i]] && !check[cur.first+mvx[i]][cur.second+mvy[i]]){
					check[cur.first +mvx[i]][cur.second+mvy[i]] = 1;
					que.push(P(cur.first+mvx[i], cur.second+mvy[i]));
			}
		}
	}
}

void process() {
	for(int i = 0; i < n; i++) {
		for(int j = 0; j < m; j++) {
			if(data[i][j] && !check[i][j]) {
				bfs(i,j);
				++cnt;
			}
		}
	}
	printf("%d\n", cnt);
}

int main() {
	while(true) {
		scanf("%d%d", &n, &m);
		if(n == 0) break;
		input();
		process();
	}
	return 0;
}

C++: #include<cstdio>
#include<utility>
#include<algorithm>
#include<set>
using namespace std;

int w,h;
pair<int,int> g[50][50];
int s[50][51];

void dfs(int x,int y,int xx,int yy){
    g[x][y]=make_pair(xx,yy);
    for(int i=max(0,x-1);i<min(x+2,h);i++){
        for(int j=max(0,y-1);j<min(y+2,w);j++){
            if(s[i][j]&&(g[i][j].first!=xx||g[i][j].second!=yy)){
                dfs(i,j,xx,yy);
            }
        }
    }
}

int main(){
    scanf("%d%d",&w,&h);
    while(w&&h){
        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                scanf("%d",&s[i][j]);
            }
        }
        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                g[i][j]=make_pair(i,j);
            }
        }
        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                if(s[i][j]==1&&g[i][j].first==i&&g[i][j].second==j){
                    dfs(i,j,i,j);
                }
            }
        }
        set<pair<int,int> > se;
        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                if(s[i][j]==1){
                    se.insert(g[i][j]);
                }
            }
        }
        printf("%ld\n",se.size());
        scanf("%d %d",&w,&h);
    }
}

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

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

int main(){
  int w,h;
  int i,j;

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