백준 4963번 - 섬의 개수

import sys
sys.setrecursionlimit(10**6)

def check(x,y):
  if not 0<=x<h or not 0<=y<w:
    return False
  if maps[x][y] == 1:
    maps[x][y] = 0
    check(x-1,y+1)
    check(x,y+1)
    check(x+1,y+1)
    check(x-1,y)
    check(x+1,y)
    check(x-1,y-1)
    check(x,y-1)
    check(x+1,y-1)
    return True
  return False

import sys
for i in sys.stdin:
  if i == "0 0\n":
    break
  w,h = map(int,i.split())
  maps = [[] for _ in range(h)]
  for i in range(h):
    for k in input().split():
      maps[i].append(int(k))

  count = 0
  for i in range(w):
    for j in range(h):
      if check(j,i):
        count += 1
  print(count)

import sys
input=sys.stdin.readline
sys.setrecursionlimit(10000)

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

def dfs(x,y):
    graph[x][y]=0
    for i in range(8):
        nx=x+dx[i]
        ny=y+dy[i]
        if 0<=nx<h and 0<=ny<w and graph[nx][ny]==1:
            dfs(nx,ny)

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