if not self.outStack: while self.inStack: self.outStack.append(self.inStack.pop()) return self.outStack[-1] def empty(self): """ :rtype: bool """ return True if (len(self.inStack)+len(self.outStack))==0 else False
Depending on your language, stack may not be supported natively. You may simulate a stack by using a list or deque (double-ended queue), as long as you use only standard operations of a stack. You may assume that all operations are valid (for example, no pop or peek operations will be...
Implement the following operations of a queue using stacks. push(x) — Push element x to the back of queue. pop() — Removes the element from in front of queue. peek() — Get the front element. empty() — Return whether the queue is empty. Java Solution classMyQueue{Stack<Integer>te...
Notes: You must useonlystandard operations of a stack -- which means onlypush to top,peek/pop from top,size, andis emptyoperations are valid. Depending on your language, stack may not be supported natively. You may simulate a stack by using a list or deque (double-ended queue), as lon...
232 Implement Queue using Stacks 用2个stack 完成 代码如下 classQueue:#initialize your data structure here.def__init__(self): self.stackA=[] self.stackB=[]#@param x, an integer#@return nothingdefpush(self, x): self.stackA.append(x)#@return nothingdefpop(self):whileself.stackA !=[]...