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>

using namespace std;
#define INF 1000007
#define MOD 1000000007
#define int long long
#define maxn 101
#define maxh 1000
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define rep(i, n) FOR(i, 0, n)
const int dx[4] = {0, 1, -1, 0}, dy[4] = {1, 0, 0, -1};
typedef std::pair<int, int> P;

vector<bool> prime(maxn + 1, true); //素数テーブル
void prime_table(void) {
    prime[0] = false;
    prime[1] = false;
    for (int i = 2; i * i <= maxn; i++) {
        if (!prime[i]) {
            continue;
        }
        for (int j = i + i; j <= maxn; j += j + i) {
            prime[j] = false;
        }
    }
}

int gcd(int a, int b) {
    return b ? gcd(b, a % b) : a;
}

int lcm(int a, int b) { return a / gcd(a, b) * b; }

bool IsPrime(int num) //素数判定
{
    if (num < 2)
        return false;
    else if (num == 2)
        return true;
    else if (num % 2 == 0)
        return false;

    double sqrtNum = sqrt(num);
    for (int i = 3; i <= sqrtNum; i += 2) {
        if (num % i == 0) {
            return false;
        }
    }

    return true;
}

vector<int> divisor(int n) //約数列挙
{
    vector<int> ret;
    for (int i = 1; i * i <= n; i++) {
        if (n % i == 0) {
            ret.push_back(i - 1);
            if (i * i != n) {
                ret.push_back((n / i) - 1);
            }
        }
    }
    sort(ret.begin(), ret.end());
    return (ret);
}

int a, b;

void f(int x) {
    while (x) {
        a++;
        b = x;
        x /= 10;
    }
}

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

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

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

C++: #include <vector>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <deque>
#include <algorithm>
#include <utility>
#include <functional>
#include <sstream>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <climits>

using namespace std;

inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v;}
template<class T> inline string toString(T x) { ostringstream sout; sout << x; return sout.str();}

typedef vector<int> vi;
typedef vector<vi>  vvi;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef long long ll;

#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define EACH(t,i,c) for(t::iretator i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)

const double EPS = 1e-10;

int seamap[52][52];
int num = 0;

void dfs(int x, int y) {
	if(seamap[x][y]) {
		seamap[x][y] = 0;

		if(seamap[x-1][y-1]) {
			dfs(x-1, y-1);
		}
		if(seamap[x][y-1]) {
			dfs(x, y-1);
		}
		if(seamap[x+1][y-1]) {
			dfs(x+1, y-1);
		}
		if(seamap[x-1][y]) {
			dfs(x-1, y);
		}
		if(seamap[x+1][y]) {
			dfs(x+1, y);
		}
		if(seamap[x-1][y+1]) {
			dfs(x-1, y+1);
		}
		if(seamap[x][y+1]) {
			dfs(x, y+1);
		}
		if(seamap[x+1][y+1]) {
			dfs(x+1, y+1);
		}
	}
}


int main() {
	int w, h;

	REP(i, 52) {
		REP(j, 52) {
			seamap[i][j] = 0;
		}
	}

	while(cin >> w >> h, (w!=0 || h!=0)) {
		FOR(i, 0, 52) {
			FOR(j, 0, 52) {
				seamap[i][j] = 0;
			}
		}

		FOR(i, 1, h+1) {
			FOR(j, 1, w+1) {
				cin >> seamap[i][j];
			}
		}

		num = 0;

		FOR(i, 1, 50) {
			FOR(j, 1, 50) {
				if(seamap[i][j]) {
					num++;
					dfs(i, j);
				}
			}
		}

		cout << num << endl;
	}

	return 0;
}

C++: #include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<cmath>
#include<stdio.h>
#include<queue>
#include <climits>
#include <map>
#include <set>
const int mod = 1e9 + 7;
const long long INF = 1LL << 60;
using namespace std;
typedef long long ll;

int w,h;
int c[50][50];
int dx[8] = {-1,-1,-1,0,0,1,1,1};
int dy[8] = {-1,0,1,-1,1,-1,0,1};

void dfs(int x,int y)
{
    c[x][y] = 0;
    for(int i = 0; i < 8; i++){
        int nx = x + dx[i] , ny = y + dy[i];
        if(0 <= nx && nx < w && 0 <= ny && ny < h && c[nx][ny] == 1){
            dfs(nx,ny);
        }
    }
    return;
}


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