대학원생이 쉽게 설명해보기

def getTotalX(a, b):
    # Write your code here
    def gcd(x, y):
        if x > y:
            s = y
            y = x
            x = s
        # x < y
        while(y > 0):
            x, y = y, x % y
        return x
    
    def lcm(x, y):
        return x * y // gcd(x, y)
    
    _lcm = a[0]
    for i in range(1, len(a)):
        _lcm = lcm(_lcm, a[i])
    
    if _lcm > 100:
        return 0
    
    _gcd = b[0]
    for i in range(1, len(b)):
        _gcd = gcd(_gcd, b[i])
            
    if (_gcd == 0) or (_lcm > _gcd):
        return 0 
    
    cnt = 0 
    for i in range(_lcm, _gcd + 1):
    	# b의 약수이고, a의 배수인 경우
        if (i % _lcm == 0) and (_gcd % i == 0):
            cnt += 1
            
    return cnt

def kangaroo(x1, v1, x2, v2):
    # Write your code here
    
    # x1 < x2이므로 속도가 같거나 크면 따라잡을 수 없음
    if v1 <= v2:
        return 'NO'
    else:
    	# v1 > v2여서 따라잡을 수 있는 경우
        # 거리 차를 속도 차가 잡을 수 있고, 같은 위치에 있을 수 있어야함
        r = (x2 - x1) % (v2 - v1)
        if r == 0:
            return 'YES'
        else:
            return 'NO'

def countApplesAndOranges(s, t, a, b, apples, oranges):
    # Write your code here
    print(sum([1 if ((apple + a) >= s and (apple + a) <= t) else 0 for apple in apples]))
    print(sum([1 if ((orange + b) >= s and (orange + b) <= t) else 0 for orange in oranges]))

def gradingStudents(grades):
    # Write your code here
    result = []
    for grade in grades:
        if grade < 38:
            result.append(grade)
        else:
            r = grade % 5
            grade = grade + (5 - r) if r > 2 else grade
            result.append(grade)
            
    return result

import sys
from collections import deque

# input = sys.stdin.readline

M, N, H = map(int, input().split())

floors = []

for _ in range(H):
    floor = []
    for _ in range(N):
        floor.append(list(map(int, input().split())))
        
    floors.append(floor)
    
queue = deque()

for i in range(H):
    for j in range(N):
        for k in range(M):
            if(floors[i][j][k] == 1):
                queue.append([i, j, k])

# 이전 문제랑 다른 점은 높이가 추가됨
dx = [1, -1, 0, 0, 0, 0]
dy = [0, 0, 1, -1, 0, 0]
dh = [0, 0, 0, 0, 1, -1]

while queue:
    height, row, col = queue.popleft()
    
    for k in range(6):
        _height = height + dh[k]
        _row = row + dy[k]
        _col = col + dx[k]
        
        if 0 <= _height < H and 0 <= _row < N and 0 <= _col < M and floors[_height][_row][_col] == 0:
            queue.append([_height, _row, _col])
            floors[_height][_row][_col] = floors[height][row][col] + 1
            
check_tot = False
result = -2

for i in floors:
    for j in i:
        for k in j:
            if(k == 0):
                check_tot = True
            result = max(result, k)
            
if check_tot:
    print(-1)
elif(result == -1):
    print(0)
else:
    print(result - 1)