[백준/Python] 14867 물통

import sys
from _collections import deque

visited = {}
a, b, c, d = map(int, sys.stdin.readline().split())

def bfs():
    queue = deque()
    queue.append((0,0))
    visited[(0,0)] = 1
    if c==0 and d==0:
        return 0

    while queue:
        x, y = queue.popleft()
        
        #Fill A
        if not visited.get((a, y)):
            queue.append((a, y))
            visited[(a, y)] = visited[(x, y)] + 1
        #Fill B
        if not visited.get((x, b)):
            queue.append((x, b))
            visited[(x, b)] = visited[(x, y)] + 1
        #Empty A
        if not visited.get((0, y)):
            queue.append((0, y))
            visited[(0, y)] = visited[(x, y)] + 1
        #Empty B
        if not visited.get((x, 0)):
            queue.append((x, 0))
            visited[(x, 0)] = visited[(x, y)] + 1
        #Move A to B        
        if x+y >= b:
            if not visited.get((x+y-b, b)):
                queue.append((x+y-b, b))
                visited[(x+y-b, b)] = visited[(x, y)] + 1
        else:
            if not visited.get((0, x+y)):
                queue.append((0, x+y))
                visited[(0, x+y)] = visited[(x, y)] + 1
        
        #move B to A
        if x+y >= a:
            if not visited.get((a, x+y-a)):
                queue.append((a, x+y-a))
                visited[(a, x+y-a)] = visited[(x, y)] + 1
        else:            
            if not visited.get((x+y, 0)):
                    queue.append((x+y, 0))    
                    visited[(x+y, 0)] = visited[(x, y)] + 1

        if visited.get((c,d)):
            if visited[(x, y)]>0:
                return visited[(x, y)]
    return -1
            
print(bfs())