标签：rem follow sum long ted while end double lis
Implement the following operations of a queue using stacks.
Example:
MyQueue queue = new MyQueue(); queue.push(1); queue.push(2); queue.peek(); // returns 1 queue.pop(); // returns 1 queue.empty(); // returns false
Notes:
push to top, peek/pop from top, size, and is empty operations are valid.class MyQueue: def __init__(self): """ Initialize your data structure here. """ self.stack_in, self.stack_out = [], [] def push(self, x: int) -> None: """ Push element x to the back of queue. """ self.stack_in.append(x) def pop(self) -> int: """ Removes the element from in front of queue and returns that element. """ self._transfer() return self.stack_out.pop() def peek(self) -> int: """ Get the front element. """ self._transfer() return self.stack_out[-1] def empty(self) -> bool: """ Returns whether the queue is empty. """ return not self.stack_in and not self.stack_out def _transfer(self): if not self.stack_out: while self.stack_in: self.stack_out.append(self.stack_in.pop()) # 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()
[LC] 232. Implement Queue using Stacks
标签：rem follow sum long ted while end double lis
原文地址：https://www.cnblogs.com/xuanlu/p/11776120.html
