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: def solve():
    from collections import deque
    
    while True:
        w, h = map(lambda x: int(x)+2, input().split())
        if w == 2:
            break

        result = 0
        a = ['0']*w
        for _ in [0]*(h-2):
            a += ['0'] + input().split() + ['0']
        a += ['0']*w

        for i in range(w*h):
            if a[i] != '1':
                continue
            a[i] = '0'
            result += 1
            dq = deque([i])
            while dq:
                j = dq.popleft()
                for dest in (j-w-1, j-w, j-w+1, j-1, j+1, j+w-1, j+w, j+w+1):
                    if a[dest] == '1':
                        a[dest] = '0'
                        dq.append(dest)
        print(result)


if __name__ == "__main__":
    solve()

Python: import sys
sys.setrecursionlimit(10**9)
ans = []
dx = (1,1,1,0,0,-1,-1,-1)
dy = (1,0,-1,1,-1,1,0,-1)

def dfs(x,y):
    st[x][y] = True
    for i,j in zip(dx,dy):
        nx = x + i
        ny = y + j
        if nx < 0 or h <= nx: continue
        if ny < 0 or w <= ny: continue
        if st[nx][ny]: continue
        if c[nx][ny]: dfs(nx,ny)

while True:
    w,h = map(int,input().split())
    if w == 0 and h == 0: break
    c = [[int(i) for i in input().split()] for _ in range(h)]
    st = [[False]*w for _ in range(h)]
    cnt = 0
    for i in range(h):
        for j in range(w):
            if st[i][j]: continue
            if c[i][j]:
                dfs(i,j)
                cnt += 1
    ans.append(cnt)

print("\n".join(map(str,ans)))

Python: # -*- coding: utf-8 -*-
def dfs(x,y):
    c[x][y] = 0
    for dx in [-1,0,1]:
        for dy in [-1,0,1]:
            nx = x + dx
            ny = y + dy
            if 0 <= nx < h and 0 <= ny < w and c[nx][ny] == 1:
                dfs(nx, ny)

while True:
    w, h = map(int,input().split())
    if w == 0 and h == 0 :
        break
    
    c = [list(map(int,input().split())) for j in range(h)]
    count = 0
    
    for i in range(h):
        for j in range(w):
            if c[i][j] == 1:
                dfs(i,j)
                count += 1

    print(count)

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

try:
    import sys

    sys.setswitchinterval(10**8)


    next_s = ((-1, 1), (0, 1), (1, 1),
              (-1, 0), (1, 0),
              (-1, -1), (0, -1), (1, -1))


    def DFS(x, y):
        if not (0 <= x < W and 0 <= y < H):
            return
        if not map_[y * W + x]:
            return

        map_[y * W + x] = 0

        for dx, dy in next_s:
            DFS(x + dx, y + dy)


    while True:
        W, H = map(int, input().split())
        if W == 0 and H == 0:
            break

        map_ = []
        for h in range(H):
            map_ += list(map(int, input().split()))
        island_num = 0
        while any(map_):
            next_idx = map_.index(1)
            x = next_idx % W
            y = next_idx // W
            DFS(x, y)
            island_num += 1

        print(island_num)
except Exception as e:
    print(e)

Python: from collections import deque
def dfs(i,j,seen):
    q=deque()
    q.append((i,j,0))
    seen[i][j]=0
    dx=[0,1,0,-1,-1,-1,1,1]
    dy=[1,0,-1,0,1,-1,1,-1]
    while q:
        X,Y,S=q.pop()
        if S==0:
            #下に遷移していくときの処理
            #q.append((V,P,1))
            for k in range(8):
                nx=X+dx[k]
                ny=Y+dy[k]
                if not(0<=nx<h and 0<=ny<w):continue
                if seen[nx][ny]==0:continue
                seen[nx][ny]=0
                q.append((nx,ny,0))
    return 1

def main(w,h):
    grid=[list(map(int,input().split())) for i in range(h)]
    ans=0
    for i in range(h):
        for j in range(w):
            if grid[i][j]:
                ans+=dfs(i,j,grid)
    print(ans)

while True:
    w,h=map(int,input().split())
    if (w,h)==(0,0):break
    main(w,h)

Python: import sys
input=sys.stdin.readline
sys.setrecursionlimit(10**6)

def dfs(x,y):
    c[x][y]='0'
    for dx in range(-1,2):
        for dy in range(-1,2):
            nx=dx+x
            ny=dy+y
            if c[nx][ny]=='1':dfs(nx,ny)

while 1:
    c=[]
    w,h=map(int,input().split())
    if w==h==0:exit()
    w+=2
    c=[list('@'*w)]
    for i in range(h):
        c+=[list('@'+input().replace(' ','').replace('\n','')+'@')]
    c+=[list('@'*w)]
    h+=2
    cnt=0

    for i in range(1,h):
        for j in range(1,w):
            if c[i][j]=='1':
                dfs(i,j)
                cnt+=1
    print(cnt)

Python: #!/usr/bin/env python
# -*- coding: utf-8 -*-

def dfs(s,Map,H,W,c):
    dxdy = [(1,0),(-1,0),(0,1),(0,-1),(1,1),(-1,-1),(-1,1),(1,-1)]
    for i in range(4):
        Map[s[0]][s[1]] = c
        nextPos = (s[0]+dxdy[i][0],s[1]+dxdy[i][1])
        if nextPos[0] >= 0 and nextPos[1] >= 0 and nextPos[0] < H and nextPos[1] < W:
            if Map[nextPos[0]][nextPos[1]] == 1:
                dfs(nextPos,Map,H,W,c)

while True:
    W,H = map(int,input().split(" "))
    if W == 0 and H == 0:
        break
    Map = [list(map(int,input().split())) for i in range(0,H)]
    c = 1
    for i in range(H):
        for j in range(W):
            if Map[i][j] == 1:
                c += 1
                dfs((i,j),Map,H,W,c)
    print(c-1)