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;
int main(void){
    int w,h;
    while (cin>>w>>h) {
        if (w==0&&h==0) {
            break;
        }
        char c;
        std::vector<vector<char>> vec(h,vector<char>(w));
        bool seen[h][w];
        for (int i=0;i<h;i++) {
            for (int j=0;j<w;j++) {
                cin>>c;
                vec[i][j]=c;
                seen[i][j]=false;
            }
        }
        int count=0;
        for (int i=0;i<h;i++) {
            for (int j=0;j<w;j++) {
                if (vec[i][j]=='1'&&seen[i][j]==false) {
                    seen[i][j]=true;
                    std::stack<pair<int,int>> stk;
                    stk.push(make_pair(i,j));
                    while (stk.size()!=0) {
                        int x=stk.top().first;
                        int y=stk.top().second;
                        if (x+1<h&&seen[x+1][y]==false&&vec[x+1][y]=='1') { //下
                            stk.push(make_pair(x+1,y));
                            seen[x+1][y]=true;
                        } else if (y+1<w&&seen[x][y+1]==false&&vec[x][y+1]=='1') { //右
                            stk.push(make_pair(x,y+1));
                            seen[x][y+1]=true;
                        } else if (x+1<h&&y-1>=0&&seen[x+1][y-1]==false&&vec[x+1][y-1]=='1') { //左下
                            stk.push(make_pair(x+1,y-1));
                            seen[x+1][y-1]=true;
                        } else if (x+1<h&&y+1<w&&seen[x+1][y+1]==false&&vec[x+1][y+1]=='1') { //右下
                            stk.push(make_pair(x+1,y+1));
                            seen[x+1][y+1]=true;
                        } else if (x-1>=0&&y-1>=0&&seen[x-1][y-1]==false&&vec[x-1][y-1]=='1') { //左上
                            stk.push(make_pair(x-1,y-1));
                            seen[x-1][y-1]=true;
                        } else if (x-1>=0&&y+1<w&&seen[x-1][y+1]==false&&vec[x-1][y+1]=='1') { //右上
                            stk.push(make_pair(x-1,y+1));
                            seen[x-1][y+1]=true;
                        } else if (x-1>=0&&seen[x-1][y]==false&&vec[x-1][y]=='1') { //上
                            stk.push(make_pair(x-1,y));
                            seen[x-1][y]=true;
                        } else if (y-1>=0&&seen[x][y-1]==false&&vec[x][y-1]=='1') { //左
                            stk.push(make_pair(x,y-1));
                            seen[x][y-1]=true;
                        } else {
                            stk.pop();
                        }
                    }
                    count++;
                }
            }
        }
        cout<<count<<endl;
    }
}

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

int dx[8] = {1,0,-1,0,1,1,-1,-1};
int dy[8] = {0,1,0,-1,1,-1,1,-1};
bool seen[60][60];
int H,W;

void dfs(const vector<vector<int> > &Grid, int y, int x){
    seen[y][x] = true;
    for(int i = 0; i < 8; i++){
        int ny = y + dy[i];
        int nx = x + dx[i];
        if(ny < 0 || ny >= H || nx < 0 || nx >= W) continue;
        if(seen[ny][nx]) continue;
        if(Grid[ny][nx] == 0) continue;
        dfs(Grid,ny,nx);
    }
}

int main(){
    while(true){
        cin >> W >> H;
        if(!H && !W) break;
        vector<vector<int> > Grid(H,vector<int>(W));
        for(int i = 0; i < H; i++){
            for(int j = 0; j < W; j++){
                cin >> Grid[i][j];
            }
        }
        memset(seen,false,sizeof(seen));
        int cnt = 0;
        for(int i = 0; i < H; i++){
            for(int j = 0; j < W; j++){
                if(Grid[i][j] == 0) continue;
                if(seen[i][j]) continue;
                dfs(Grid,i,j);
                cnt++;
            }
        }
        cout << cnt << endl;
    }
    return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
int H,W,k[100][100],n[100][100],color=1,i,j,l,m,o,r;
int main(){while(true){memset(n,0,sizeof(n));r=0;cin>>H>>W;if(H==0){break;}for(i=0;i<H;i++){for(j=0;j<W;j++){cin>>k[i][j];}}
for(i=0;i<H;i++){for(j=0;j<W;j++){if(r==1){color++;}r=0;if(k[i][j]==1 && n[i][j]==0){n[i][j]=color;for(l=0;l<100;l++){
	for(m=0;m<H;m++){for(o=0;o<W;o++){if(n[m][o]==color){
		for(int p=-1;p<=1;p++){for(int q=-1;q<=1;q++){if(m-p>=0 && m-p<H){if(o-q>=0 && o-q<W){n[m][o]=color;}}}}
	}}}
}}}}
cout<<color<<endl;}
}

C++: #include <iostream>

using namespace std;

int w, h, cnt;
int island[51][51];
int dx[] = {1, 1, 0, -1, -1, -1,  0,  1};
int dy[] = {0, 1, 1,  1,  0, -1, -1, -1};

bool check(int nx, int ny){

  if(nx < 0 || w <= ny || ny < 0 || h < ny)return false;
  else return true;

}

void dfs(int sy, int sx){

  island[sy][sx] = 0;

  for(int i = 0 ; i < 8 ; i++){
    int nx = sx + dx[i];
    int ny = sy + dy[i];
    if(!check(nx, ny)) continue;
    if(island[ny][nx]) dfs(ny, nx);
  }
}

int main(void){

  while(cin >> w >> h, w || h){

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

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

C++: #include<iostream>
#include<cmath>
#include<cstdio>
#include<algorithm>
#include<vector>
#include<cstring>

using namespace std;

#define INF 999999999

int map[52][52];
bool ch[52][52];
int ans;

void dfs(int map[52][52], bool c[52][52], int x, int y){
	//cout << x << " " << y << " " << ans << endl;
	c[x][y] = 1;
	if(map[x-1][y]==1 && c[x-1][y]==0) dfs(map,c,x-1,y);
	if(map[x-1][y-1]==1 && c[x-1][y-1]==0) dfs(map,c,x-1,y-1);
	if(map[x-1][y+1]==1 && c[x-1][y+1]==0) dfs(map,c,x-1,y+1);
	if(map[x+1][y]==1 && c[x+1][y]==0) dfs(map,c,x+1,y);
	if(map[x+1][y-1]==1 && c[x+1][y-1]==0) dfs(map,c,x+1,y-1);
	if(map[x+1][y+1]==1 && c[x+1][y+1]==0) dfs(map,c,x+1,y+1);
	if(map[x][y-1]==1 && c[x][y-1]==0) dfs(map,c,x,y-1);
	if(map[x][y+1]==1 && c[x][y+1]==0) dfs(map,c,x,y+1);
}

int main(){
	int i, j, w, h;
	while(1){
		cin >> w >> h;
		if(!w) break;
		for(i=0;i<=h+1;i++){
			for(j=0;j<=w+1;j++){
				if(i==0||i==h+1||j==0||j==w+1)map[i][j]=0;
				else cin >> map[i][j];
				ch[i][j] = 0;
			}
		}
		ans = 0;
		for(i=1;i<=h;i++){
			for(j=1;j<=w;j++){
				if(map[i][j]&&!ch[i][j]){
					dfs(map,ch,i,j);
					ans++;
				}
			}
		}
		
		cout << ans << endl;
	}
	return 0;
}