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 <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <regex>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <valarray>
#include <vector>
using namespace std;

using ll = long long;
using ld = long double;
const int INF = 1e9;
const double EPS = 1e-9;
const ll MOD = 1e9 + 7;

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

void dfs(int y, int x, vector<vector<int>> &c)
{
  c[y][x] = 0;
  for (int i = 0; i < 8; ++i)
  {
    int ny = y + dy[i], nx = x + dx[i];
    if (0 <= nx && nx < c[0].size() && 0 <= ny && ny < c.size() && c[ny][nx])
      dfs(ny, nx, c);
  }
}

int main()
{
  int w, h;
  while (cin >> w >> h, w || h)
  {
    vector<vector<int>> c;
    c.clear();
    c.shrink_to_fit();
    c.assign(h, vector<int>(w));
    for (int i = 0; i < h; ++i)
    {
      for (int j = 0; j < w; ++j)
      {
        cin >> c[i][j];
      }
    }
    int cnt = 0;
    for (int i = 0; i < h; ++i)
    {
      for (int j = 0; j < w; ++j)
      {
        if (c[i][j])
        {
          dfs(i, j, c);
          cnt++;
        }
      }
    }
    cout << cnt << endl;
  }

  return 0;
}

C++: #if 0

#endif

#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;

int W, H;
int x[8] = {1,0,-1,0,1,1,-1,-1};
int y[8] = {0,-1,0,1,1,-1,1,-1};

bool in_map(int h, int w) {
  return (1 <= h && h <= H && 1 <= w && w <= W);
}

int main() {
  while(cin >> W >> H && W > 0) {
    int M[55][55];
    for (int h = 1; h <= H; h++) {
      for (int w = 1; w <= W; w++)
        cin >> M[h][w];
    }
    queue<pair<int,int>> Q;
    int ans = 0;
    for (int sh = 1; sh <= H; sh++) {
      for (int sw = 1; sw <= W; sw++) {
        if (M[sh][sw] == 1) {
          ans++;
          Q.push(make_pair(sh,sw));
          M[sh][sw] = 0;
          while (!Q.empty()) {
            pair<int,int> p = Q.front();
            Q.pop();
            int h = p.first; int w = p.second;
            for (int i = 0; i < 8; i++) {
              int nh = h+y[i]; int nw = w+x[i];
              if (in_map(nh, nw) && M[nh][nw] == 1) {
                Q.push(make_pair(nh, nw));
                M[nh][nw] = 0;
              }
            }
          }
        }
      }
    }

    cout << ans << endl;
  }
}

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

#define FOR(i, a, b) for(long long int i=(a);i<=(b);i++)
#define RFOR(i, a, b) for(long long int i=(a);i>=(b);i--)
#define MOD 1000000007
#define INF 1000000000 //2000000000
#define LLINF 1000000000000000000 //9000000000000000000
#define PI 3.14159265358979

using namespace std;
typedef long long int ll;
typedef pair< long long int, long long  int> P;

int c[50][50] = {};

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

int main(void) {
	
	while (1) {
		int h, w;
		int count = 0;

		cin >> w >> h;
		if (h == 0) {
			break;
		}
		

		FOR(i, 0, h - 1) {
			FOR(t, 0, w - 1) {
				cin >> c[i][t];
			}
		}
		FOR(i, 0, h - 1) {
			FOR(t, 0, w - 1) {
				if (c[i][t] == 0) {
					continue;
				}
				
				dfs(t, i, h, w);
				count++;
			}
		}
		cout << count << endl;
	}

}

C++: /************************************
 * ???????????¢?´¢??§??¶?????°?????°??????????????°?????? *
 ************************************/

#include <iostream>
#include <queue>
#include <map>

#define LAND '1'  //??? char???
#define SEA  '0'   //??? char???

using namespace std;

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

/*8??????*/
int dx[] = {1,1,0,-1,-1,-1, 0, 1};
int dy[] = {0,1,1, 1, 0,-1,-1,-1};

bool input(vector< vector<char> > &m);
void delete_island(vector< vector< char > > &m, int x, int y);
void output(vector< vector< char> > m);


int main(){
  int w, h;
    
  while(cin >> w >> h, w && h){
    vector< vector< char > > m(h+2, vector<char>(w+2));
    input(m);
    
    int island = 0;
    for(int y = 0; y < m.size(); y++){
      for(int x = 0; x < m[y].size(); x++){
	if(m[y][x] == LAND){
	  delete_island(m,x,y);
	  island++;
	}
      }
    }
    cout << island << endl;
  }
}


bool input(vector< vector<char> > &m){
  for(int y = 0; y < m.size(); y++){
    for(int x = 0; x < m[y].size(); x++){
      if(y == 0 || x == 0 ||
	 y == m.size()-1 || x == m[y].size()-1){
	m[y][x] = SEA;
      }else{
	if(!(cin >> m[y][x])) return false;
      }
    }
  }
  return true;
}


 void delete_island(vector< vector< char > > &m, int x, int y){
   queue< pair< int, int > > q;
   q.push(make_pair(x,y));

   while(!(q.empty())){
     pair<int, int> cur = q.front();
     q.pop();
     if(m[cur.second][cur.first] == LAND){
       m[cur.second][cur.first] = SEA;
       for(int i = 0; i < sizeof(dx)/sizeof(int); i++){
	 q.push(make_pair(cur.first+dx[i],cur.second+dy[i]));
       }
     }
   }
}

void output(vector< vector< char> > m){
  for(int y = 0; y < m.size()-1; y++){
    for(int x = 0; x < m[y].size()-1; x++){
      cout << m[y][x] << " ";
    }
    cout << endl;
  }
  cout << endl;
}

C++: #include<bits/stdc++.h>
typedef long long ll;
typedef long double ld;
using namespace std;
ll H, W;
ll field[110][110];
ll dx[8] = { 0, 1, 0,-1, 1, 1,-1,-1 };
ll dy[8] = { 1, 0,-1, 0, 1,-1, 1,-1 };
void dfs(ll y, ll x) {
	field[y][x] = 0;
	for (ll i = 0; i < 8; i++) {
		ll ny = y + dy[i];
		ll nx = x + dx[i];
		if (nx >= 0 && nx < H && ny >= 0 && ny < W) {
			if (field[ny][nx] == 1)
				dfs(ny, nx);
		}
	}
}
int main() {
	while (cin >> H >> W) {
		if (H == 0 && W == 0) break;
		ll cnt = 0;
		for (ll i = 0; i < W; i++) {
			for (ll j = 0; j < H; j++) {
				cin >> field[i][j];
			}
		}
		for (ll y = 0; y < W; y++) {
			for (ll x = 0; x < H; x++) {
				if (field[y][x] == 1) {
					dfs(y, x);
					cnt++;
				}
			}
		}
		cout << cnt << endl;
	}
}