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<fstream>

using namespace std;

	ifstream fin;
	ofstream fout;

	//http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1160&lang=jp

	int gomi = 0;

	int a[52][52] = {};
	int check(int, int);

	int main(){

		fin.open("input.txt");
		fout.open("output.txt");

		//		int w = 0, h = 0;
		int width = 0, height = 0;
		int count = 0;


		while (1){
			for (int i = 0; i < 50; i++)
				for (int j = 0; j < 50; j++)
					a[i + 1][j + 1] = 0;

			cin >> width >> height;
			if (width == 0 && height == 0)break;

			for (int i = 0; i < height; i++){
				for (int j = 0; j < width; j++){
					//初期化
					gomi = a[i + 1][j + 1] = 0;

					cin >> a[i + 1][j + 1];
				}
			}

			for (int i = 0; i < height; i++){
				for (int j = 0; j < width; j++){
					if (a[i + 1][j + 1] == 1){
						check(i + 1, j + 1);
//						a[i + 1][j + 1] = 1;
						count++;
					}
				}
			}
			cout << count << endl;
			fout << count << endl;

			//初期化
			count = 0;
			for (int i = 0; i < height; i++){
				for (int j = 0; j < width; j++){
					a[i + 1][j + 1] = 0;
				}
			}
		}
	}

	int check(int y, int x){
		for (int i = -1; i <= 1; i++){
			for (int j = -1; j <= 1; j++){
				if (i + j != 0 || i - j != 0){
					if (a[y + i][x + j] == 1){
						a[y + i][x + j] = 0;
						check(y + i, x + j);
					}
				}
			}
		}
		return 0;
	}

/*	int check(int y, int x){
		if (a[y + 1][x] == 1){
			a[y + 1][x] = 0;
			check(y + 1, x);
		}
		//-----------------------------
		if (a[y][x + 1] == 1){
			a[y][x + 1] = 0;
			check(y, x + 1);
		}
		//-----------------------------
		if (a[y - 1][x] == 1){
			a[y - 1][x] = 0;
			check(y - 1, x);
		}
		//-----------------------------
		if (a[y][x - 1] == 1){
			a[y][x - 1] = 0;
			check(y, x - 1);
		}
		//-----------------------------
		if (a[y + 1][x + 1] == 1){
			a[y + 1][x + 1] = 0;
			check(y + 1, x + 1);
		}
		//-----------------------------
		if (a[y + 1][x - 1] == 1){
			a[y + 1][x - 1] = 0;
			check(y + 1, x - 1);
		}
		//-----------------------------
		if (a[y - 1][x + 1] == 1){
			a[y - 1][x + 1] = 0;
			check(y - 1, x + 1);
		}
		//-----------------------------
		if (a[y - 1][x - 1] == 1){
			a[y - 1][x - 1] = 0;
			check(y - 1, x - 1);
		}
		//-----------------------------
		return 0;
	}*/

C++: #include <iostream>
#include <vector>
#include <numeric>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <string>
#include <cstring>
#include <queue>
#define myfor(i,N) for(i=0;i<N;i++)
#define myforFL(i,f,l) for(i=f;i<l;i++)
#define myforInv(i,N) for(i=N;i>=0;i--)
#define myforFLInv(i,f,l) for(i=f;i>l;i--)

using namespace std;
int dx[]={1,-1,0,0,1,-1,1,-1},dy[]={0,0,1,-1,1,-1,-1,1};
int w,h;
vector<vector<int> >c(50, vector<int>(50));
vector<vector<bool> >done(50, vector<bool>(50,false));

int dfs(int x, int y){
	int i;
	if(c[x][y] == 0)return 0;
	
	myfor(i,8){
		if(x+dx[i]>=0&&x+dx[i]<w && y+dy[i]>= 0 && y+dy[i] < h )if(!done[x+dx[i]][y+dy[i]]&& c[x+dx[i]][y+dy[i]] == 1){
			done[x+dx[i]][y+dy[i]] = true;
			dfs(x+dx[i],y+dy[i]);
		}
	}
	done[x][y] = true;
	return 1;
}
int mainloop(int win, int hin){
	int i,j,count=0;
	w = win,h=hin;
	
	myfor(i,w)myfor(j,h)cin >> c[i][j];
	myfor(i,w)myfor(j,h){
		if(!done[i][j])count+= dfs(i,j);
	}
	return count;
}

int main(){
	int win=1,hin=1,i;
	vector<int> ans;
	while(win != 0 && hin != 0){
		cin >> win >> hin;
		int cnt=0;
		if(win != 0 && hin != 0){
			done.assign(50,vector<bool>(50,false));
			ans.push_back(mainloop(hin,win));
		}
	}
	myfor(i,ans.size())cout << ans[i] << endl;
	return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <stack>
#include <utility>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)
#define FST first
#define SEC second

typedef pair <int,int> pxy;

int dfs(int map[][50],int w,int h){
  int dd[10]={0, 1, 1, 1, 0, -1, -1, -1, 0, 1};
  stack <pxy> s;
  int num=0;
  rep(y,h){
    rep(x,w){
      if(map[x][y]==1){
	s.push(pxy(x,y));
	while(!s.empty()){
	  int cx=s.top().FST,cy=s.top().SEC;
	  s.pop();
	  map[cx][cy]=0;
	  rep(r,8){
	    int nx=cx+dd[r],ny=cy+dd[r+2];
	    if(nx<0||w<=nx||ny<0||h<=ny||map[nx][ny]==0) continue;
	    s.push(pxy(nx,ny));
	  }
	}
	num++;
      }
    }
  }
  return num;
}

int main() {
  for(;;){
    int w,h,x,y;
    scanf("%d %d",&w,&h);
    int map[50][50];
    if(w==0&&h==0) break;
    rep(i,h){
      rep(j,w){
	cin >> map[j][i];
      }
    }
    cout << dfs(map,w,h) << endl;
  } 
}

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

int main() {
    int n, m;
    int dx[] = {1, 0, -1, 0, 1, 1, -1, -1};
    int dy[] = {0, 1, 0, -1, 1, -1, 1, -1};
    while (cin >> m >> n, n || m) {
        vector<vector<int>> v(n, vector<int>(m));
        for (auto& i : v) for (auto& j : i) cin >> j;

        int count = 0;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                if (v[i][j] == 0) continue;
                count++;
                queue<pair<int,int>> que;
                que.push(make_pair(i, j));

                while (que.size()) {
                    auto p = que.front();
                    que.pop();
                    int x = p.first;
                    int y = p.second;

                    if (v[x][y] == 0) continue;

                    v[x][y] = 0;

                    for (int k = 0; k < 8; k++) {
                        int nx = x + dx[k];
                        int ny = y + dy[k];

                        if (0 <= nx && nx < n && 0 <= ny && ny < m && v[nx][ny] == 1) {
                            que.push(make_pair(nx, ny));
                        }
                    }
                }
            }
        }

        cout << count << endl;
    }

    return 0;
}