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 <string>
#include <algorithm>
#include <vector>
#include <cmath>
#include <cstdlib>
#include <tuple>
using namespace std;
using ll=long long;
using R=double;

int w,h;

int dx[8] = {0, 1, 1, 1, 0, -1, -1, -1};
int dy[8] = {1, 1, 0, -1, -1, -1, 0, 1};
int field[50][50];

void dfs(int w, int h){
	field[h][w] = 0;

	for(int nh=h-1;nh<h+2;nh++){
	    for(int nw=w-1;nw<w+2;nw++){
	      if(field[nh][nw]==1&&0<=nh&&0<=nw&&nh<h&&nw<w)dfs(nw,nh);
	    }
	  }
	return;
}

int main(){
	while(1){
		cin >> w >> h;
		if(w==0 and h==0){
			break;
		}

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

		int count = 0;

		for(int i = 0; i < h; i++){
			for(int j = 0; j < w; j++){
				if(field[i][j]==1){
					count++;
					dfs(j,i);
				}
			}
		}
		cout << count << endl;
	}
	return 0;
}

C++: #include<cstdio>
using namespace std;
void func(int,int);
int a,b;
int sima[51][51];
int cnt;
int main(void)
{
	int i,j,x,y;
	scanf("%d",&a);
	scanf("%d",&b);
	while(!(a==0 && b==0)){
		
		for(i=0;i<b;i++){
			for(j=0;j<a;j++){
				scanf("%d",&sima[i][j]);
			}
		}
		cnt=0;
		for(i=0;i<b;i++){
			for(j=0;j<a;j++){
				if(sima[i][j]==1){
					func(i,j);
					cnt++;
				}
			}
		}
		printf("%d\n",cnt);
		scanf("%d",&a);
		scanf("%d",&b);
	}
	return 0;
}
void func(int y,int x)
{
	if(y-1>=0){
		if(sima[y-1][x]==1){
			sima[y-1][x]=0;
			func(y-1,x);
		}
	}
	if(x-1>=0){
		if(sima[y][x-1]==1){
			sima[y][x-1]=0;
			func(y,x-1);	
		}
	}
	if(y+1<=a){
		if(sima[y+1][x]==1){
			sima[y+1][x]=0;
			func(y+1,x);
		}
	}
	if(x+1<=b){
		if(sima[y][x+1]==1){
			sima[y][x+1]=0;
			func(y,x+1);
		}
	}
	if(y-1>=0 && x+1<=b){
		if(sima[y-1][x+1]==1){
			sima[y-1][x+1]=0;
			func(y-1,x+1);
		}
	}
	if(y-1>=0 && x-1>=0){
		if(sima[y-1][x-1]==1){
			sima[y-1][x-1]=0;
			func(y-1,x-1);
		}
	}
	if(y+1<=a && x+1<=b){
		if(sima[y+1][x+1]==1){
			sima[y+1][x+1]=0;
			func(y+1,x+1);
		}
	}
	if(y+1<=a && x-1>=0){
		if(sima[y+1][x-1]==1){
			sima[y+1][x-1]=0;
			func(y+1,x-1);
		}
	}
}

C++: #include<bits/stdc++.h>
#define rep(i,a,b) for(int i=int(a);i<int(b);++i)
using namespace std;
typedef long long ll;
int INF = (1LL << 30) - 1;
int MOD = 1e9+7;
int H,W;
void dfs(int h,int w,vector<vector<int> > &table){
    //cout << h << " " << w << endl;
    table[h][w] = 0;
    int dx[] = {-1,-1,-1,0 ,0,1 ,1,1};
    int dy[] = {-1,0 ,1 ,-1,1,-1,0,1};
    rep(i,0,8){
        int nx = w + dx[i];
        int ny = h + dy[i];
        if (nx >= W || nx < 0 || ny >= H || ny < 0) continue;
        if(table[ny][nx])dfs(ny,nx,table);
    }
}
main(){
    cin >> H >> W;
    vector< vector<int> > table;
    while(H){
        table = vector< vector<int> > (H,vector<int>(W) );
        rep(i,0,H)rep(j,0,W)cin >> table[i][j];
        int cnt = 0;
        rep(i,0,H)rep(j,0,W){
            if(table[i][j] == 1){
                dfs(i,j,table);
                cnt++;
            }
        }
        cout << cnt << endl;
        cin >> H >> W;
    }
}

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

#define rep(i, j, n) for(int i=j;i<n;++i)
#define all(i) i.begin(),i.end()
#define rall(i) i.rbegin(),i.rend()
#define inf 1e9
#define Puts(x) puts(x? "Yes":"No")
const int mod = 1e9 + 7;

int gcd(int n, int m) {return (m == 0? n : gcd(m, n % m));}
int dx[] = {0, 1, 0, -1, 1, 1, -1, -1};
int dy[] = {1, 0, -1, 0, 1, -1, 1, -1};

typedef pair<int, int> pi;
typedef long long i64;

template <class T> using vt = vector<T>;
template <class T> using vvt = vector<vector<T>>;

int w, h;

void dfs(int y, int x, auto &grid, auto &visited) {
  if(!grid[y][x] || visited[y][x]) return;

  visited[y][x] = true;
  rep(i, 0, 8) {
    dfs(y + dy[i], x + dx[i], grid, visited);
  }
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  while(cin >> w >> h, w && h) {
    vvt<bool> grid(h + 2, vt<bool>(w + 2, false));
    vvt<bool> visited(h + 2, vt<bool>(w + 2, false));

    rep(i, 1, h + 1) {
      rep(j, 1, w + 1) {
        int c;
        cin >> c;
        grid[i][j] = !!c;
      }
    }

    int cou = 0;
    rep(i, 1, h + 1) {
      rep(j, 1, w + 1) {
        if(!grid[i][j] || visited[i][j]) continue;

        cou++;
        dfs(i, j, grid, visited);
      }
    }
    cout << cou << endl;
  }
}

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

using namespace std;

#define rep(i, n) for(int i = 0; i < n; i++)
typedef long long ll;
template<typename T> bool chmax(T &a, T b) {if(a <= b){a = b; return true;}return false;}
template<typename T> bool chmin(T &a, T b) {if(a >= b){a = b; return true;}return false;}
#define sea 0
#define rand 1

int W, H;
vector<vector<int> > c;
vector<vector<bool> > memo;

int dw[8] = {0,1,1,1,0,-1,-1,-1};
int dh[8] = {1,1,0,-1,-1,-1,0,1};
void dfs(int h, int w){
    memo[h][w] = true;
    for(int i = 0; i < 8; i++){
        int next_h = h + dh[i];
        int next_w = w + dw[i];
        //地図の範囲外でないかの確認
        if(next_w < 0 || next_h < 0 || W <= next_w || H <= next_h)continue;
        //行き先が見探索であるか確認
        if(memo[next_h][next_w])continue;
        dfs(next_h, next_w);
    }
}

main(void) {
    while (true) {
        cin >> W >> H;
        if(W + H == 0)break;
        memo.resize(H);
        rep(h,H){
            memo[h].resize(W);
            rep(w,W)memo[h][w] = false;
        }
        c.resize(H);
        for(int h = 0; h < H; h++){
            c[h].resize(W);
            for(int w = 0; w < W; w++){
                cin >> c[h][w];
                if(c[h][w] == sea)memo[h][w] = true;
            }
        }
        int ans = 0;
        rep(h,H){
            rep(w, W){
                if(!memo[h][w]){
                    dfs(h, w);
                    ans++;
                }
            }
        }
        cout << ans << endl;
    }
}