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++: #if 0
20分

#endif
#include <iostream>
#include <memory>
#include <vector>
#include <string>
#include <algorithm>
#include <assert.h>
#include <complex>
#include <queue>
#define rep(i,n) for(int i=0, i##_len=(n); i<i##_len; ++i)
using namespace std;
using ll = long long;
ll ll_max = numeric_limits<ll>::max();
ll ll_min = numeric_limits<ll>::min();
int int_max = numeric_limits<int>::max();
int int_min = numeric_limits<int>::min();
int W, H;
int islands[50][50];
queue<pair<int, int> > now;
vector<pair<int, int> > not_reached;
int dirs[8][2] = {{-1, 0}, {0, -1}, {1, 0}, {0, 1}, {1, -1}, {1, 1}, {-1, 1}, {-1, -1}};
bool check_point(pair<int, int> point) {
    bool ret = true;
    ret &= point.first > -1;
    ret &= point.second > -1;
    ret &= point.first < H;
    ret &= point.second < W;
    ret &= islands[point.first][point.second] == 1;
    return ret;
}
void bfs() {
    while (!now.empty()) {
        pair<int, int> start = now.front();
        now.pop();
        for (auto dir : dirs) {
            auto next = make_pair(start.first + dir[0], start.second + dir[1]);
            if (check_point(next)) {
                // cout << "next:" << next.first << ", " << next.second << endl;
                now.push(next);
                auto next_it = find(not_reached.begin(), not_reached.end(), next);
                if (next_it != not_reached.end())
                    not_reached.erase(next_it);
                islands[next.first][next.second] = 2;
            }
        }
    }
}
int main(void){
    cin.tie(0);
    ios::sync_with_stdio(false);

    while (cin >> W >> H && W && H) {
        rep(h, H) {
            rep(w, W) {
                cin >> islands[h][w];
                if (islands[h][w] == 1)
                    not_reached.push_back(make_pair(h, w));
            }
        }
        int cnt = 0;
        while (!not_reached.empty()) {
            ++cnt;
            queue<pair<int, int> > empty;
            swap(now, empty);
            now.push(not_reached.back());
            not_reached.pop_back();
            bfs();
        }
        cout << cnt << endl;
    }

    return 0;
}

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

using namespace std;

using ll = long long;

int w, h;
vector< vector<int> > c, island;

int dx[] = {1, -1, 0, 0, 1, -1, 1, -1};
int dy[] = {0, 0, 1, -1, 1, -1, -1, 1};

void dfs(int x, int y, int id) {

    island[y][x] = id;

    for(int i = 0; i < 8; i++) {

        int nx = x + dx[i];
        int ny = y + dy[i];

        if(nx < 0 || nx >= w || ny < 0 || ny >= h)
            continue;

        if(c[ny][nx] == 1 && island[ny][nx] != id)
            dfs(nx, ny, id);

    }

}

int main(){

    cin.tie(0);
    ios::sync_with_stdio(false);

    int ans;

    while(cin >> w >> h && w) {

        c.assign(h, vector<int>(w));
        island.assign(h, vector<int>(w, -1));
        ans = 0;

        for(int y = 0; y < h; y++)
            for(int x = 0; x < w; x++)
                cin >> c[y][x];

        for(int x = 0; x < w; x++)
            for(int y = 0; y < h; y++)
                if(c[y][x] == 1 && island[y][x] == -1)
                    dfs(x, y, ans++);

        cout << ans << endl;

    }
}

C++: #include <bits/stdc++.h>
#define err(args...) {}
#ifdef DEBUG
#include "_debug.cpp"
#endif
using namespace std;
using ll = long long;
bool hori(int di, int dj) { return abs(di) == 0 and abs(dj) == 1; }
bool vert(int di, int dj) { return abs(di) == 1 and abs(dj) == 0; }
bool diag(int di, int dj) { return abs(di) == 1 and abs(dj) == 1; }
template <typename signature> using f = const function<signature>&;
void flood(vector<vector<int>>& a, f<bool(int, int)> can, f<void(int, int, int, int)> f) {
    int n = a.size() - 2, m = a[0].size() - 2;
    vector<vector<bool>> vis(n + 2, vector<bool>(m + 2));
    function<void(int, int, int, int)> dfs = [&](int i, int j, int from_i, int from_j) {
        if(a[i][j] and not vis[i][j]) {
            f(i, j, from_i, from_j);
            vis[i][j] = true;
            for(int di = -1; di <= 1; di++) {
                for(int dj = -1; dj <= 1; dj++) {
                    if(can(di, dj)) {
                        dfs(i + di, j + dj, i, j);
                    }
                }
            }
        }
    };
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= m; j++) {
            if(not vis[i][j]) {
                dfs(i, j, 0, 0);
            }
        }
    }
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int w, h;
    while(cin >> w >> h and w and h) {
        vector<vector<int>> a(h + 2, vector<int>(w + 2));
        for(int i = 1; i <= h; i++) {
            for(int j = 1; j <= w; j++) {
                cin >> a[i][j];
            }
        }
        int ans = 0;
        flood(a, [](int di, int dj) { return true; }, [&](int i, int j, int from, int) {
            ans += not from;
        });
        cout << ans << endl;
    }
    return 0;
}