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;
enum class WalkingResult { undef, walked };
enum class LandS { sea, land };
using LMap = vector<vector<LandS>>;

void solve(int w, int h) {
    LMap lMap(h, vector<LandS>(w));
    vector<pair<int, int>> lands;
    for (int i = 0; i < h; ++i) {
        for (int j = 0; j < w; ++j) {
            int t;
            cin >> t;
            lMap[i][j] = t == 1 ? LandS::land : LandS::sea;
            if (t == 1) lands.push_back(make_pair(i, j));
        }
    }

    vector<vector<WalkingResult>> wMap(h, vector<WalkingResult>(w, WalkingResult::undef));
    int count = 0;
    stack<pair<int, int>> s;
    for (int i = 0; i < lands.size(); ++i) {
        pair<int, int> x = lands[i];
        bool already = wMap[x.first][x.second] == WalkingResult::walked;
        if (already) continue;
        s.push(x);
        while(!s.empty()) {
            pair<int, int> pos = s.top();
            s.pop();
            bool out = pos.first < 0 || h <= pos.first || pos.second < 0 || w <= pos.second;
            if (out) continue;
            bool sea = lMap[pos.first][pos.second] == LandS::sea;
            bool walked = wMap[pos.first][pos.second] == WalkingResult::walked;
            if (sea || walked) continue;
            wMap[pos.first][pos.second] = WalkingResult::walked;
            s.push(make_pair(pos.first + 1, pos.second));
            s.push(make_pair(pos.first - 1, pos.second));
            s.push(make_pair(pos.first, pos.second + 1));
            s.push(make_pair(pos.first, pos.second - 1));
            s.push(make_pair(pos.first - 1, pos.second - 1));
            s.push(make_pair(pos.first + 1, pos.second - 1));
            s.push(make_pair(pos.first - 1, pos.second + 1));
            s.push(make_pair(pos.first + 1, pos.second + 1));
        }
        count++;
    }
    cout << count << endl;
}

int main() {

    while (true) {
        int w, h;
        cin >> w >> h;
        if (w == 0 && h == 0) break;
        solve(w, h);
    }
    return 0;
}

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

int w,h;
int c[51][51];
bool used[51][51];

void dfs(int x,int y) {
    used[x][y]=1;
    for(int dx=-1; dx<=1; ++dx) {
        for(int dy=-1; dy<=1; ++dy) {
            int xx=x+dx;
            int yy=y+dy;
            if(x+dx < 0 || x+dx >=h) continue;
            if(y+dy < 0 || y+dy >=w) continue;
            if(used[xx][yy] || c[xx][yy]==0) continue;
            dfs(xx,yy);
        }
    }
}

int main() {
    while(true) {
        int ans=0;
        cin>>w>>h;
        if(!w) return 0;
        for(int i=0; i<h; ++i) {
            for(int j=0; j<w; ++j) {
                cin>>c[i][j];
                used[i][j]=0;
            }
        }
        for(int i=0; i<h; ++i) {
            for(int j=0; j<w; ++j) {
                if(used[i][j] || c[i][j]==0) continue;
                //cerr<<i<<" "<<j<<endl;
                dfs(i,j);
                ans++;
            }
        }
        cout<<ans<<endl;
    }
}

C++: #include <iostream>
#include <string>
#include <cstring>
#include <fstream>
#include <random>
#include <cmath>
#include <iomanip>
#include <climits>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <map>
#include <deque>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <list>
#include <unordered_map>
#include <bitset>
#include <sstream>
#include <new>
#include <typeinfo>
#include <iterator>

typedef long long ll;
typedef unsigned long long ull;
constexpr ll mop = 1000000007;
constexpr ll mop2 = 998244353;

using namespace std;

void dfs(const ll& x, const ll& y, vector<vector<bool>>& grid, const ll& h, const ll & w) {
	grid[x][y] = false;
	for (ll dx = -1; dx <= 1; dx++) {
		for (ll dy = -1; dy <= 1; dy++) {
			ll nextx = x + dx;
			ll nexty = y + dy;
			if (0 <= nextx && nextx < h && 0 <= nexty && nexty < w && grid[nextx][nexty] == true) {
				dfs(nextx, nexty, grid, h, w);
			}
		}
	}
}

int main() {
	while (true) {
		ll w, h;
		cin >> w >> h;
		if (w == 0 && h == 0) {
			break;
		}
		vector<vector<bool>> grid(h);
		for (ll i = 0; i < h; i++) {
			grid[i].resize(w);
			for (ll j = 0; j < w; j++) {
				ll tmp;
				cin >> tmp;
				grid[i][j] = (tmp == 1 ? true : false);
			}
		}
		ll ans = 0;
		for (ll i = 0; i < h; i++) {
			for (ll j = 0; j < w; j++) {
				if (grid[i][j] == true) {
					ans++;
					dfs(i, j, grid, h, w);
				}
			}
		}
		cout << ans << endl;
	}
}

C++: #include <iostream>
#include <string>
#include <utility>
#include <stack>
#include <vector>
#include <queue>
#include <algorithm>
#include <map>
#include <climits>
#include <set>
#include <numeric>
#include <iomanip>
#include <cmath>
#include <cstring>
using namespace std;
int grid[50][50];
bool used[50][50];
int move_h[8] = {-1, 1, 0, 0, -1, 1, -1, 1};
int move_w[8] = {0, 0, -1, 1, 1, -1, -1, 1};

void dfs(int cur_h, int cur_w, int h, int w){
  used[cur_h][cur_w] = true;
  for(int i = 0; i < 8; i++){
    int next_h = cur_h + move_h[i];
    int next_w = cur_w + move_w[i];

    if(0 <= next_h && next_h < h && 0 <= next_w && next_w < w 
        && !used[next_h][next_w] && grid[next_h][next_w] == 1){
      dfs(next_h, next_w, h, w);
    }
  }
}
int main(){
  while(true){
    int w;
    int h;
    cin >> w >> h;
    if(w == 0 && h == 0){
      break;
    }
    for(int i = 0; i < h; i++){
      for(int j = 0; j < w; j++){
        cin >> grid[i][j];
        used[i][j] = false;
      }
    }

    int ans = 0;
    for(int i = 0; i < h; i++){
      for(int j = 0; j < w; j++){
        if(!used[i][j] && grid[i][j] == 1){
          ans ++;
          dfs(i, j, h, w);
        }
      }
    }
    cout << ans << endl;
  }
  return 0;
}

C++: #include<iostream>
using namespace std;
void dfs(int,int);
int box[51][51];
int main(){
  int w,h,i,I,a;
  while(1){
    a=0;
    cin>>w>>h;
    if(w==0&&h==0) break;
    for(i=0;i<=h+1;i++){
      for(I=0;I<=w+1;I++){
	box[i][I]==0;
      }
    }
    for(i=1;i<=h;i++){
      for(I=1;I<=w;I++){
	cin>>box[i][I];
      }
    }
    for(i=1;i<=h;i++){
      for(I=1;I<=w;I++){
	if(box[i][I]==1){
	  dfs(i,I);
	  a++;
	}
      }
    }
    cout<<a<<endl;
  }
  return 0;
}
  void dfs(int i,int I){
  if(box[i][I]==0) return;
  box[i][I]=0;
  dfs(i,I+1);
  dfs(i+1,I+1);
  dfs(i+1,I);
  dfs(i+1,I-1);
  dfs(i,I-1);
  dfs(i-1,I-1);
  dfs(i-1,I);
  dfs(i-1,I+1);
  }