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)
	}
}

Python: # -*- coding: utf-8 -*-

import sys

def input(): return sys.stdin.readline().strip()
def list2d(a, b, c): return [[c] * b for i in range(a)]
def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)]
def list4d(a, b, c, d, e): return [[[[e] * d for j in range(c)] for j in range(b)] for i in range(a)]
def ceil(x, y=1): return int(-(-x // y))
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(N=None): return list(MAP()) if N is None else [INT() for i in range(N)]
def Yes(): print('Yes')
def No(): print('No')
def YES(): print('YES')
def NO(): print('NO')
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
MOD = 10 ** 9 + 7

# 8方向
directions = ((1,0),(-1,0),(0,1),(0,-1),(1,1),(-1,-1),(-1,1),(1,-1))
cnt = 0

def rec(cur, prev):

    global cnt
    h, w = cur // (W+2), cur % (W+2)
    if visited[h][w]:
        return
    visited[h][w] = 1
    # 初回のみ、島カウントを足す
    if prev == -1:
        cnt += 1

    for d in directions:
        h2, w2 = h + d[0], w + d[1]
        if grid[h2][w2]:
            rec(h2*(W+2)+w2, cur)
    return 

while True:

    W, H = MAP()
    if H == W == 0:
        break

    grid = list2d(H+2, W+2, 0)
    for i in range(1, H+1):
        row = LIST()
        for j in range(1, W+1):
            grid[i][j] = row[j-1]

    visited = list2d(H+2, W+2, 0)
    cnt = 0
    for i in range(1, H+1):
        for j in range(1, W+1):
            if grid[i][j]:
                rec(i*(W+2)+j, -1)
    print(cnt)

Python: from collections import defaultdict,deque
import sys,heapq,bisect,math,itertools,string,queue,datetime
sys.setrecursionlimit(10**8)
INF = float('inf')
mod = 10**9+7
eps = 10**-7
def inp(): return int(sys.stdin.readline())
def inpl(): return list(map(int, sys.stdin.readline().split()))
def inpl_str(): return list(sys.stdin.readline().split())

dx = [1,1,1,0,0,0,-1,-1,-1]
dy = [1,0,-1,1,0,-1,1,0,-1]

def dfs(x,y):
    global MAP
    if MAP[y][x] == 0:
        return
    else:
        MAP[y][x] = 0
        for i in range(9):
            dfs(x+dx[i],y+dy[i])


while True:
    W,H = inpl()
    if W == 0:
        break
    else:
        MAP = [[0] + inpl() + [0] for i in range(H)]
        MAP = [[0]*(W+2)] + MAP + [[0]*(W+2)]
        ans = 0
        for y in range(1,H+1):
            for x in range(1,W+1):
                if MAP[y][x] == 1:
                    ans += 1
                    dfs(x,y)
        print(ans)

Python: import sys
sys.setrecursionlimit(2500)
 
def erase(x, y):
    c[y][x] = '0'
    for dx, dy in ((1, 0), (1, 1), (0, 1), (-1, 1), (-1, 0), (-1, -1), (0, -1), (1, -1)):
        nx, ny = x + dx, y + dy
        if 0 <= nx < w and 0 <= ny < h and c[ny][nx] == '1':
            erase(nx, ny)
 
while True:
    w, h = map(int, sys.stdin.readline().split())
    if w == h == 0:
        break
    c = [sys.stdin.readline().split() for _ in range(h)]
    ans = 0
    for y in range(h):
        for x in range(w):
            if c[y][x] == '1':
                ans += 1
                erase(x, y)
    print(ans)

Python: def solver():
    w, h = map(int, input().split())
    if w == 0 and h == 0:
        return None
    islands = set()
    counter = 2
    c = [[0] + [int(x) for x in input().split()] + [0]  for _ in range(h)]
    c = [[0 for _ in range(w+2)]] + c + [[0 for _ in range(w+2)]]
    for i in range(1, h+1):
        for j in range(1, w+1):
            if c[i][j] > 0:
                neighbour = {c[i-1][j-1], c[i-1][j], c[i-1][j+1], c[i][j-1]}
                if max(neighbour) > 1:
                    c[i][j] = max(neighbour)
                    if len(neighbour) > 2:
                        islands -= {max(neighbour)}
                else:
                    c[i][j] = counter
                    islands |= {counter}
                    counter += 1
    return len(islands)

outputs = []
while(True):
    ans = solver()
    if ans == None:
        break
    outputs.append(ans)
print('\n'.join(map(str, outputs)))

Python: # -*- coding: utf-8 -*-
#150 島は幾つある？
h,w=1,1

count=0
anser=0

def search(x,y):
    #マップの外側か壁の場合は何もしない
    #print(x,y)

    global count
    count+=1
    if x<0 or x>w-1 or y<0 or y>h-1 or map_data[y][x]==0:
 
        return
        
    
    #以前に到達していたら何もしない
    if reached[y][x] ==0:
         return

    reached[y][x]=0
    
    #print("aa")



    search(x+1,y)#右
    search(x-1,y)#左
    search(x,y+1)#上
    search(x,y-1)#下
    search(x-1,y-1)
    search(x-1,y+1)
    search(x+1,y-1)
    search(x+1,y+1)



while h!=0 and w!=0: 
    anser=0
    count=1
    #グラフの入力方法------

    w,h=map(int ,raw_input().split())
    if h==0 and w==0:
        break

    map_data = [[0]*w for _ in range(h)]
    reached = [[1]*w for _ in range(h)]

    for i in range(h):
        ct = raw_input().split()
       
        for j in range(w):
            map_data[i][j] = int(ct[j])
            reached [i][j]=int(ct[j])
            if ct[j]==1:
                sx=j
                sy=i

    t=0
    a=0
    while a<=h:
       if 1 in reached[t%h]:         
            search(reached[t%h].index(1),t%h)
            anser+=1
            #print("count",count)
            count=1
            a=0
       elif count==h:
                break
       t+=1
       a+=1

    print(anser)