Go: ///
// File:  1160.go
// Author: ymiyamoto
//
// Created on Sun Mar  4 20:45:57 2018
//
package main

import (
	"fmt"
)

var w, h int
var graph [][]string

func dfs(visited [][]bool, x, y int) {
	visited[x][y] = true

	for i := -1; i <= 1; i++ {
		for j := -1; j <= 1; j++ {
			dx := x + i
			dy := y + j
			if 0 <= dx && dx < h && 0 <= dy && dy < w && graph[dx][dy] == "1" && !visited[dx][dy] {
				dfs(visited, dx, dy)
			}
		}
	}
}

func main() {
	for {
		fmt.Scan(&w, &h)
		if w == 0 && h == 0 {
			break
		}

		graph = make([][]string, h)
		for i := range graph {
			graph[i] = make([]string, w)
		}

		for i := 0; i < h; i++ {
			for j := 0; j < w; j++ {
				var s string
				fmt.Scan(&s)
				graph[i][j] = s
			}
		}

		visited := make([][]bool, h)
		for i := range visited {
			visited[i] = make([]bool, w)
		}

		count := 0
		for i := range graph {
			for j := range graph[i] {
				if graph[i][j] == "1" && !visited[i][j] {
					dfs(visited, i, j)
					count++
				}
			}
		}

		fmt.Println(count)
	}
}

C++: #include <bits/stdc++.h>
using namespace std;

int Count;
int w,h;
bool area[51][51]={};
int dx[8]={0,1,1,1,0,-1,-1,-1};
int dy[8]={1,1,0,-1,-1,-1,0,1};

void bfs(int x,int y){
  int X,Y;
  queue<pair<int,int> > Q;
  Q.push(make_pair(x,y));
  area[x][y]=0;
  while(!Q.empty()){
    pair<int,int> p1=Q.front();
    X=p1.first;
    Y=p1.second;
    Q.pop();
    for(int i=0;i<8;i++){
      if((X+dx[i]<=-1||Y+dy[i]<=-1)||(X+dx[i]>=w||Y+dy[i]>=h))continue;
      if(area[X+dx[i]][Y+dy[i]]==1){
        Q.push(make_pair(X+dx[i],Y+dy[i]));
        area[X+dx[i]][Y+dy[i]]=0;
      }
    }
  } 
  return;
}

int main(){
  int I;
  while(cin>>w>>h,w){
    Count=0;
    for(int i=0;i<h;i++){
      for(int j=0;j<w;j++){
        cin>>I;
        area[j][i]=I;
      }
    }

    for(int i=0;i<h;i++){
      for(int j=0;j<w;j++){
        if(area[j][i]==1){
          bfs(j,i);
          Count++;
        }
      }
    }
    cout<<Count<<endl;
  }
  return 0;
}

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;
}