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++: //
// Created by elegant-belltree on 15/06/03.
//

#include <iostream>
#include <set>

using namespace std;

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

    while (cin>>w>>h && (w>0 || h>0)) {
        int label=2;
        set<int> labels;

        for (int n = 0; n < 2; ++n) {
            for (int i = 0; i < h; ++i) {
                for (int j = 0; j < w; ++j) {
                    if(n==0) {
                        cin >> c[j][i];
                    }
                    if (0<c[j][i]) {
                        for (int k = -1; k < n+1 && i+k<h; ++k) {
                            for (int l = -1; (n!=0 || k!=0 || l!=0) && l < 2 && j + l < w; ++l) {
                                if (-1 < i + k && -1 < j + l && 0 < c[j + l][i + k] && (c[j][i] == 1 || c[j + l][i + k] < c[j][i])) {
                                    if(n==1){
                                        labels.erase(c[j][i]);
                                    }
                                    c[j][i] = c[j + l][i + k];
                                }
                            }
                        }
                        if (c[j][i] == 1) {
                            c[j][i] = label++;
                            labels.insert(c[j][i]);
                        }
                    }
                }
            }
        }
        /*for (int m = 0; m < h; ++m) {
            for (int i = 0; i < w; ++i) {
                cout<<c[i][m]<<" ";
            }
            cout<<endl;
        }*/
        cout<<labels.size()<<endl;
    }
    return 0;
}

C++: 
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstdlib>
#include <cmath>
#include <vector>
#include <ctime>
#include <string>
#include <map>
#include <stack>
#include <queue>

using namespace std;

int w, h;
const int MAX = 50;
int c[MAX][MAX];


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

int main(void){

	for(int i = 0; i < MAX ; i++){
		for(int j = 0; j < MAX; j++){
			c[i][j] = 0;
		}
	}

	cin >> w >> h;
	while(w != 0 && h != 0){
		int ans = 0;
		for(int i = 0; i < h ; i++){
			for(int j = 0; j < w; j++){
				cin >> c[i][j];
			}
		}

		for(int i = 0; i < h ; i++){
			for(int j = 0; j < w; j++){
				if(c[i][j] == 1){
					check(i, j);
					ans++;
				}
			}
		}
		cout << ans << endl;

		cin >> w >> h;
	}
	
    return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i,n) for(int i=0; i<(n); i++)
#define FOR(i,a,n) for(int i=(a); i<(n); i++)
#define all(v) v.begin(), v.end()
#define fi first
#define se second
using namespace std;
using ll = long long;
using P = pair<int, int>;
const int INF = 1e9;
const int MOD = 1e9+7;

int H, W;
int mat[50][50];
const int dh[] = {-1, -1, -1, 0, 0, 1, 1, 1};
const int dw[] = {-1, 0, 1, -1, 1, -1, 0, 1};

void dfs(int h, int w) {
	mat[h][w] = 0;
	rep(i, 8) {
		int nh = h+dh[i], nw = w+dw[i];
		if (nh>=0 && nh<H && nw>=0 && nw<W && mat[nh][nw]==1) dfs(nh, nw);
	}
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	while (true) {
		cin >> W >> H;
		if (W+H == 0) break;
		
		memset(mat, 0, sizeof(mat));

		rep(i, H) {
			rep(j, W) cin >> mat[i][j];
		}

		int cnt = 0;
		rep(i, H) rep(j, W) {
			if (mat[i][j]==1) {
				dfs(i, j);
				cnt++;
			}
		}

		cout << cnt << endl;
	}
}

C++: #include<bits/stdc++.h>
#define REP(i, n) for (int i = 0; i < n ; i++)
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define whole(f, x, ...) ([&](decltype((x)) whole) { return (f)(begin(whole), end(whole), ## __VA_ARGS__); })(x) // decltypeで型取得、引数があればva_argsのところに入れる
using namespace std;
typedef long long ll; // long longをllでかけるようにした
const int INF = 1e9;
int n, m;
char W[100][100];

void dfs(int y, int x){
    W[y][x] = '0';
    for(int dx = -1; dx <= 1; dx++){
        for(int dy = -1; dy <= 1; dy++){
            int nx = dx + x;
            int ny = dy + y;
            if(W[ny][nx] == '1' and 0 <= nx and nx < n and 0 <= ny and ny < m) dfs(ny, nx);
        }
    }
    return ;
}

int main(void){
    while(true){
        cin >> n >> m;
        if(n == 0 and m == 0) return 0;
        REP(i, m){
            REP(j, n){
                cin >> W[i][j];
            }
        }

        int ans = 0;
        REP(i, m){
            REP(j, n){
                if(W[i][j] == '1'){
                    dfs(i, j);
                    ans++;
                }
            }
        }
        cout << ans << endl;
    }
}

C++: #include<iostream>
using namespace std;
int g = 0;
int w, h;
int a[50][50];
int ans = 0;
void track(int i, int j) {
	for (int l = -1; l <= 1; l++) {
		for (int m = -1; m <= 1; m++) {
			/*int li = l + i;
			int mj = m + j;*/
			if (l+i < h && m+j < w && l+i >= 0 && m+j >= 0 && a[l+i][m+j] == 1) {
				g = 1;
				a[l+i][m+j] = 0;
				/*for (int i = 0; i < h; i++) {
					for (int j = 0; j < w; j++) {
						cout << a[i][j];
						if (j == 4) { cout << endl; }
					}*/
					track(l+i, m+j);
				}
			}
		}
		/*for (int i = 0; i < h; i++) {
			for (int j = 0; j < w; j++) {
				cout << a[i][j];
				if (j == 4)cout << endl;
			}
		}*/
	}
int main() {
	while (1) {
		cin >> w >> h;
		if (w == 0 && h == 0) { return 0; }
		for (int i = 0; i < h; i++) {
			for (int j = 0; j < w; j++) {
				cin >> a[i][j];
			}
		}
		for (int i = 0; i < h; i++) {
			for (int j = 0; j < w; j++) {
				track(i, j);
				if (g == 1) { ans++; }
				g = 0;
			}
		}
		cout << ans << endl;
		ans = 0;
	}
}