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 <iostream>
#include <vector>

using namespace std;


int read_map(vector< vector <int> >& map,int &w, int &h){
  cin >> w >>  h;
  if (w == 0 && h == 0){
    return 0;
  }
  map.reserve(h);
  for (int i = 0; i < h ; ++i) map[i].resize(w);
  for (int i = 0; i < h; ++i)
  {
    for (int j = 0; j < w; ++j)
    {
      cin >> map[i][j];
    }
  }
  return 1;
}


bool island_check(vector<vector<int> >& map, int i, int j){
  if (map[i][j] == 1){
    return true;
  }
  return false;
}

void walk_island(vector<vector<int> >& map, int i, int j, int w, int h){
  int start_i, start_j;
  start_i = i;
  start_j = j;
  while (++j < w){
    if (island_check(map, i, j))
    {
      map[i][j] = 2;
      walk_island(map, i, j, w, h);
    }else{
      break;
    }
  }
  j = start_j;
  while (--j >= 0){
    if (island_check(map, i, j))
    {
      map[i][j] = 2;
      walk_island(map, i, j, w, h);
    }else{
      break;
    }
  }
  while (++i < h){
    if (island_check(map, i, j))
    {
      map[i][j] = 2;
      walk_island(map, i, j, w, h);
    }else{
      break;
    }
  }
  i = start_i;
  while (--i >= 0){
    if (island_check(map, i, j))
    {
      map[i][j] = 2;
      walk_island(map, i, j, w, h);
    }else{
      break;
    }
  }
  i = start_i;
  j = start_j;
  while (++i < h && ++j < w){
    if (island_check(map, i, j))
    {
      map[i][j] = 2;
      walk_island(map, i, j, w, h);
    }else{
      break;
    }
  }
  i = start_i;
  j = start_j;
  while (--i >= 0 && ++j < w){
    if (island_check(map, i, j))
    {
      map[i][j] = 2;
      walk_island(map, i, j, w, h);
    }else{
      break;
    }
  }
  i = start_i;
  j = start_j;
  while (--i >= 0 && --j >= 0){
    if (island_check(map, i, j))
    {
      map[i][j] = 2;
      walk_island(map, i, j, w, h);
    }else{
      break;
    }
  }
  while (++i < h && --j >= 0){
    if (island_check(map, i, j))
    {
      map[i][j] = 2;
      walk_island(map, i, j, w, h);
    }else{
      break;
    }
  }
}

int search_island_num(vector< vector <int> >& map, int w, int h){
  int island_count = 0;
  for (int i = 0; i < h; ++i)
  {
    for (int j = 0; j < w; ++j)
    {
      if(map[i][j] == 1){
        island_count++ ;
        map[i][j] = 2;
        walk_island(map, i, j, w, h);
      }
    }
  }
  return island_count;
}

int main(){
  vector< vector<int> > map;
  int w, h;
  while (read_map(map, w, h) != 0) {
    cout << search_island_num(map, w, h) << endl;
    map.clear();
  }
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
long long w, h;
std::vector<std::vector<int>> c;
void dfs(int x, int y){
    c[x][y] = 0;
    for(int i = -1; i <= 1; i++){
        for(int j = -1; j <= 1; j++){
            int newx = x + i, newy = y + j;
            if(0 <= newx && newx < h && 0 <= newy && newy < w && c[newx][newy] == 1) dfs(newx, newy);
        }
    }
}
int main(){
    while(1){
        w = 0;
        h = 0;
        std::cin >> w >> h;
        if(w == 0 && h == 0) break;
        std::vector<std::vector<int>> l;
        c = l;
        c.resize(h, std::vector<int> (w));
        for(int i =0 ; i < h; i++){
            for(int j = 0; j < w; j++) std::cin >> c[i][j];
        }
        long long ans = 0;
        for(int i = 0; i < h; i++){
            for(int j = 0; j < w; j++){
                if(c[i][j] == 1) {
                    dfs(i, j);
                    ans++;
                }
            }
        }
        std::cout << ans << std::endl;
    }
}

C++: #include <iostream>

using namespace std;

int W, H;
int field[55][55];

void input(void){
	cin >> W;
	cin >> H;

	for(int i = 0;i < H;i++){
		for(int j = 0;j < W;j++){
			cin >> field[j][i];
		}
	}
}

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

	for(int dx = -1;dx <= 1;dx++){
		for(int dy = -1;dy <= 1;dy++){
			int nx = x + dx, ny = y + dy;
			if(0 <= nx && nx < W && 0 <= ny && ny < H && field[nx][ny] == 1) dfs(nx, ny);
		}
	}

	return ;
}

int main(){
	while(1){
		int res = 0;
		input();
		if(W == 0 && H == 0) break;

		for(int i = 0;i < H;i++){
			for(int j = 0;j < W;j++){
				if(field[j][i] == 1){
					dfs(j, i);
					res++;
				}
			}
		}

		cout << res << endl;
	}

	return 0;
}

C++: #include <algorithm>
#include <cmath>
#include <climits>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <cassert>

using namespace std;

#define LOG(...) printf(__VA_ARGS__)
//#define LOG(...)
#define FOR(i,a,b) for(int i=(int)(a);i<(int)(b);++i)
#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())
#define RSORT(c) sort((c).rbegin(),(c).rend())
#define CLR(a) memset((a), 0 ,sizeof(a))

typedef long long ll;
typedef unsigned long long ull;
typedef vector<bool> vb;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vb> vvb;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

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

const int L_MAP = 50 + 2;
bool field[L_MAP][L_MAP];

const bool LAND = true;
const bool SEA = false;

void dfs(int x, int y){
    if(field[y][x] == SEA)
        return;

    field[y][x] = SEA;
    FOR(dy, -1, 1 + 1){
        FOR(dx, -1, 1 + 1){
            dfs(x+ dx, y + dy);
        }
    }
}

int main() {
    int w, h;
    while(cin >> w >> h, w|h){
        fill_n((bool *)field, L_MAP * L_MAP, SEA);
        REP(y, h){
            REP(x, w) {
                cin >> field[y + 1][x + 1];
            }
        }

        int cnt = 0;
        REP(y, h) {
            REP(x, w) {
                if (field[y + 1][x + 1] == LAND) {
                    dfs(x + 1, y + 1);
                    cnt ++;
                }
            }
        }

        cout << cnt << endl;
    }

}

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

int main() {
	int W, H;
	while (cin >> W >> H) {
		if (W == 0) return 0;
		vector<vector<int> > V(H, vector<int>(W));
		for (int i = 0; i < H; i++) {
			for (int j = 0; j < W; j++) cin >> V[i][j];
		}
		int ANS = 0;
		for (int i = 0; i < H; i++) {
			for (int j = 0; j < W; j++) {
				if (V[i][j] == 1) {
					ANS++;
					queue<pair<int, int> > Q;
					Q.push({ i, j });
					V[i][j] = 0;
					while (!Q.empty()) {
						pair<int, int> P = Q.front();
						Q.pop();
						for (int k = -1; k <= 1; k++) {
							for (int l = -1; l <= 1; l++) {
								int NX = P.first + k, NY = P.second + l;
								if (0 <= NX && NX < H && 0 <= NY && NY < W) {
									if (V[NX][NY] == 1) {
										V[NX][NY] = 0;
										Q.push({ NX, NY });
									}
								}
							}
						}
					}
				}
			}
		}
		cout << ANS << endl;
	}
}