from collections import deque
class MyStack:
def __init__(self):
self.q = deque()
def push(self, x: int) -> None:
self.q.append(x)
for _ in range(len(self.q) - 1):
self.q.append(self.q.popleft())
def pop(self) -> int:
return self.q.popleft()
def top(self) -> int:
return self.q[0]
def empty(self) -> bool:
return len(self.q) == 0
# Your MyStack object will be instantiated and called as such:
# obj = MyStack()
# obj.push(x)
# param_2 = obj.pop()
# param_3 = obj.top()
# param_4 = obj.empty()
새로운 요소가 들어오면 그 전에 있던 요소들을 새로운 요소 뒤에 다 넣는다.