Go: // AOJ 1160: How Many Islands? http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1160

package main

import (
	"bufio"
	"container/list"
	"fmt"
	"os"
	"strconv"
)

var SEA = 0
var LAND = 1

func nextInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

func discoverIslands(M, V [][]int, H, W int) int {
	// 島を探す
	queue := list.New()
	islands := 0
	for i := 1; i <= H; i++ {
		for j := 1; j <= W; j++ {
			// 訪問済みの土地ならスキップ
			if V[i][j] == 1 {
				continue
			}

			// 訪問中の土地が海なら訪問済みにしてスキップ
			if M[i][j] == SEA {
				V[i][j] = 1
				continue
			}

			// 未訪問の陸地が見つかったので
			// 島の数を1つ増やし、この陸地から辿れる陸地を訪問していく
			islands++
			queue.PushBack([]int{i, j})

			for queue.Len() > 0 {
				cur := queue.Remove(queue.Front()).([]int)
				h, w := cur[0], cur[1]
				if V[h][w] == 1 {
					continue
				}
				V[h][w] = 1

				// 全方向に未訪問の陸地がないか探索
				for v := -1; v <= 1; v++ {
					for l := -1; l <= 1; l++ {
						dh := h + v
						dw := w + l
						if M[dh][dw] == LAND && V[dh][dw] == 0 {
							queue.PushBack([]int{dh, dw})
						}
					}
				}
				/*
					if M[h-1][w] == LAND {
						queue.PushBack([]int{h - 1, w})
					}
					if M[h-1][w+1] == LAND {
						queue.PushBack([]int{h - 1, w + 1})
					}
					if M[h][w+1] == LAND {
						queue.PushBack([]int{h, w + 1})
					}
					if M[h+1][w+1] == LAND {
						queue.PushBack([]int{h + 1, w + 1})
					}
					if M[h+1][w] == LAND {
						queue.PushBack([]int{h + 1, w})
					}
					if M[h+1][w-1] == LAND {
						queue.PushBack([]int{h + 1, w - 1})
					}
					if M[h][w-1] == LAND {
						queue.PushBack([]int{h, w - 1})
					}
					if M[h-1][w-1] == LAND {
						queue.PushBack([]int{h - 1, w - 1})
					}
				*/
			}
		}
	}
	return islands
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	for {
		W, H := nextInt(sc), nextInt(sc)

		if W == 0 && H == 0 {
			break
		}
		// Initialize map and visted list
		M := make([][]int, H+2)
		V := make([][]int, H+2)
		for i := 0; i < H+2; i++ {
			M[i] = make([]int, W+2)
			V[i] = make([]int, W+2)
		}
		for i := 1; i <= H; i++ {
			for j := 1; j <= W; j++ {
				M[i][j] = nextInt(sc)
			}
		}

		islands := discoverIslands(M, V, H, W)

		fmt.Println(islands)
	}
}

C++: #include <iostream>
using namespace std;
int w,h;
int in[100][100];
bool seen[100][100];
int ans =0;
bool flag = false;

void solve(int i,int j){
    cout << i << " " << j << endl;
    if(i < 0 || j < 0 || i >= h || j >= w){
        return;
    }
    if(seen[i][j]){
        return;
    }
    if(in[i][j] == 0){
        return;
    }
    seen[i][j] = true;
    solve(i-1,j-1);
    solve(i-1,j);
    solve(i-1,j+1);
    solve(i,j-1);
    solve(i,j+1);
    solve(i+1,j-1);
    solve(i+1,j);
    solve(i+1,j+1);

}
int main(){
    cin >> w >> h;
    for(int i=0;i<h;i++){
        for(int j=0;j<w;j++){
            cin >> in[i][j];
        }
    }
    for(int i=0;i<h;i++){
        for(int j=0;j<w;j++){
            if(seen[i][j] == true || in[i][j] == 0){
            }
            else{
                solve(i,j);
                ans++;
            }
            
        }
    }
    cout << ans << endl;
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <stack>
#include <string>
#include <map>
#include <functional>
#include <cmath>
#include <cstdio>
using namespace std;

#define PI 4*atan(1)

int w,h;
int c[50][50];

void dfs(int i, int j){
  c[i][j] = 0;
  for(int dx = -1; dx <= 1; dx++){
    for(int dy = -1; dy <= 1; dy++){
      int nx = i + dx, ny = j + dy;
      if(0 <= nx && nx < h && 0 <= ny && ny < w && c[nx][ny] == 1){
        dfs(nx, ny);
      }
    }
  }
}

void solve(){
  int cnt = 0;
  for(int i = 0; i < h; i++){
    for(int j = 0; j < w; j++){
      if(c[i][j] == 1){
        dfs(i, j);
        cnt++;
      }
    }
  }
  cout << cnt << endl;
}

int main(){
  while(cin >> w >> h && w, h){
    for(int i = 0; i < h; i++){
      for(int j = 0; j < w; j++){
        cin >> c[i][j];

      }
    }
    solve();
  }
}

C++: #include <bits/stdc++.h>
using namespace std;
int w, h;
vector<vector<int>> a(55, vector<int>(55, 0));
int ct;

void dfs(int y, int x) {
  a[y][x] = 0;
  for(int i = -1; i <= 1; ++i) {
    for(int j = -1; j <= 1; ++j) {
      int ny = y + i, nx = x + j;
      if(0 <= ny && ny < h && 0 <= nx && nx < w && a[ny][nx] == 1) {
        dfs(ny, nx);
      }
    }
  }
}

int main() {
  for(;;) {
    scanf("%d %d", &w, &h);
    if(w == 0 && h == 0) break;
    for(int i = 0; i < h; ++i) {
      for(int j = 0; j < w; ++j) {
        scanf("%d", &a[i][j]);
      }
    }

    for(int i = 0; i < h; ++i) {
      for(int j = 0; j < w; ++j) {
        if(a[i][j] == 1) {
          ++ct;
          dfs(i, j);
        }
      }
    }
    printf("%d\n", ct);
    ct = 0;
    a.clear();
  }
  return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <queue>

using namespace std;

typedef pair<int, int> p;

int t_x[] = {1, 1, 1, 0, -1, -1, -1, 0};
int t_y[] = {1, 0, -1, -1, -1, 0, 1, 1};

int field[52][52];  

int main()
{
  while (true) {
    memset(field, 0, sizeof field);
    int width, height;
    scanf("%d %d", &width, &height);
    
    if (width == 0 && height == 0) break;
    
    for (int i = 1; i <= height; i++) {
      for (int j = 1; j <= width; j++) {
	scanf(" %d", &field[i][j]);
      }
    }
    
    queue<p> que;
    int c = 0;

    for (int i = 1; i <= height; i++) {
      for (int j = 1; j <= width; j++) {
	if (field[i][j] == 1) {
	  c++;
	  que.push(p(i, j));
	  field[i][j] = 0;
	  while (!que.empty()) {
	    p tmp = que.front();
	    que.pop();
	    //field[tmp.second][tmp.first] = 0;
	    //cout << tmp.first << ", " << tmp.second << endl;
	    for (int k = 0; k < 8; k++) {
	      int tx = tmp.second + t_x[k];
	      int ty = tmp.first + t_y[k];
	      //cout << ty << ", "<< tx << " =  "<< field[ty][tx] << endl;
	      if (field[ty][tx] == 1) {
		field[ty][tx] = 0;
		que.push(p(ty, tx));
	      }
	    }
	    //cout << endl;
	    //cout << i << " " << j << endl;
	    for (int k = 1; k <= height; k++) {
	      for (int l = 1; l <= width; l++) {
		//cout << field[k][l] << " ";
	      }
	      //cout << endl;
	    }
	    //cout << endl;
	  }
	}
      }     
    }
    cout << c << endl;
  }
  return 0;
}

C++: #include <cstdio>

int w, h;
int c[50][50];

void dfs(int a, int b){
	for(int i = 0; i < 3; i++){
		for(int j = 0; j < 3; j++){
			int A = a+i-1, B = b+j-1;
			if(0<=A&&A<w&&0<=B&&B<h&&c[A][B]){
				c[A][B] = 0;
				dfs(A,B);
			}
		}
	}
}

int main(){
	while(scanf("%d%d", &w, &h),w||h){
		int ans = 0;
		for(int i = 0; i < h; i++){
			for(int j = 0; j < w; j++){
				scanf("%d", &c[j][i]);
			}
		}
		for(int i = 0; i < w; i++){
			for(int j = 0; j < h; j++){
				if(c[i][j]){
					c[i][j] = 0;
					ans++;
					dfs(i,j);
				}
			}
		}
		printf("%d\n", ans);
	}
}

C++: /*
URL: http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1160&lang=jp
?????????: How Many Islands?
?????°:
18:49 ?????????????????????????§£?????????
*/
#include <iostream>
using namespace std;

int dat[52][52]; // ??¨?????????1???????????£?????°

void delete_island_from(int i, int j)
{
	int dx[8] = {-1,-1,-1, 0,  0, 1, 1, 1};
	int dy[8] = {-1, 0, 1,-1,  1,-1, 0, 1};

	dat[i][j] = 0;
	for(int k=0;k<8;k++) {
		if(dat[i+dx[k]][j+dy[k]]) {
			delete_island_from(i+dx[k],j+dy[k]);
		}
	}
}


int main()
{
	while(true){ // data set
		//dat???0????????¢
		for(int i=0;i<52;i++){
			for(int j=0;j<52;j++){
				dat[i][j]=0;
			}
		}

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

		for(int i=0; i<h;i++) {
			for(int j=0;j<w;j++) {
				cin >> dat[i+1][j+1]; // ??¨?????????1???????????£?????°
			}
		}

		int ans = 0;
		while(true) {
			for(int i=0; i<h+2;i++) { // ????????£?????°??????
				for(int j=0;j<w+2;j++) {
					if(dat[i][j] == 1){
						delete_island_from(i,j);
						ans++;
						goto label1;
					}
				}
			} // all is ocean
			cout << ans << endl;
			break;


			label1: ;
		}
	}
}