八. 栈和单调栈

普通栈：

剑指 Offer 09. 用两个栈实现队列

class CQueue:    def __init__(self):        self.s1, self.s2 = [], []    def appendTail(self, value: int) -> None:        self.s1.append(value)    def deleteHead(self) -> int:        if not self.s2:            while self.s1: self.s2.append(self.s1.pop())        return self.s2.pop() if self.s2 else -1# Your CQueue object will be instantiated and called as such:# obj = CQueue()# obj.appendTail(value)# param_2 = obj.deleteHead()

232. 用栈实现队列

面试题 03.04. 化栈为队

class MyQueue:    def __init__(self):