Stacks

Challenge Implement a queue (FIFO) using only two stacks. The implemented queue should support all the functions of a normal queue (push, peek, pop, and empty). Solution class MyQueue: def __init__(self): self.stack1 = [] self.stack2 = [] self.mypeek = None def push(self, x: int) -> None: if not self.stack1: self.mypeek = x self.stack1.insert(0, x) return None def pop(self) -> int: while len(self.stack1): val = self.stack1.pop(0) self.stack2.insert(0, val) if self.stack2: ret = self.stack2.pop(0) while len(self.stack2): val = self.stack2.pop(0) self.stack1.insert(0, val) return ret def peek(self) -> int: if self.stack1: self.mypeek = self.stack1[len(self.stack1)-1] return self.mypeek if self.peek else None def empty(self) -> bool: if len(self.stack1) == 0: return True return False