# Leetcode 232. Implement Queue using Stack


class MyQueue:

    def __init__(self):
        self.stack1 = []
        self.stack2 = []

    def push(self, x: int) -> None:
        self.stack1.append(x)

    def pop(self) -> int:
        if not self.empty():
            while self.stack1:
                num = self.stack1.pop()
                self.stack2.append(num)
            output = self.stack2.pop()
            while self.stack2:
                num = self.stack2.pop()
                self.stack1.append(num)
            return output

    def peek(self) -> int:
        if not self.empty():
            while self.stack1:
                num = self.stack1.pop()
                self.stack2.append(num)
            output = self.stack2[-1]
            while self.stack2:
                num = self.stack2.pop()
                self.stack1.append(num)
            return output

    def empty(self) -> bool:
        return len(self.stack1) == 0
        


# Your MyQueue object will be instantiated and called as such:
# obj = MyQueue()
# obj.push(x)
# param_2 = obj.pop()
# param_3 = obj.peek()
# param_4 = obj.empty()

2023.08.13 AC

class MyQueue:

    def __init__(self):
      self.stack = []

    def push(self, x: int) -> None:
      self.stack.append(x)
    
    def pop(self) -> int:
      n = len(self.stack)
      temp = []
      i = 0
      while i < n:
        temp.append(self.stack.pop())
        i += 1
      res = temp.pop()
      n = len(temp)
      i = 0
      while i < n:
        self.stack.append(temp.pop())
        i += 1
      return res
    
    def peek(self) -> int:
      n = len(self.stack)
      temp = []
      i = 0
      while i < n:
        temp.append(self.stack.pop())
        i += 1
      res = temp[-1]
      n = len(temp)
      i = 0
      while i < n:
        self.stack.append(temp.pop())
        i += 1
      return res
    
    def empty(self) -> bool:
      return len(self.stack) == 0


# Your MyQueue object will be instantiated and called as such:
# obj = MyQueue()
# obj.push(x)
# param_2 = obj.pop()
# param_3 = obj.peek()
# param_4 = obj.empty()