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225. Implement Stack using Queues

题目

Implement the following operations of a stack using queues.

• push(x) -- Push element x onto stack.
• pop() -- Removes the element on top of the stack.
• top() -- Get the top element.
• empty() -- Return whether the stack is empty.

Example :

MyStack stack = new MyStack();

stack.push(1);
stack.push(2);  
stack.top();   // returns 2
stack.pop();   // returns 2
stack.empty(); // returns false

Note:

• You must use only standard operations of a queue -- which means only push to back, peek/pop from front, size, and is empty operations are valid.
• Depending on your language, queue may not be supported natively. You may simulate a queue by using a list or deque (double-ended queue), as long as you use only standard operations of a queue.
• You may assume that all operations are valid (for example, no pop or top operations will be called on an empty stack).

题目大意

题目要求用队列实现一个栈的基本操作：push(x)、pop()、top()、empty()。

解题思路

按照题目要求实现即可。

Documentation

Index

• type MyStack
  • func Constructor225() MyStack
  • func (this *MyStack) Empty() bool
  • func (this *MyStack) Pop() int
  • func (this *MyStack) Push(x int)
  • func (this *MyStack) Top() int

Types

type MyStack

type MyStack struct {
	// contains filtered or unexported fields
}

func Constructor225

func Constructor225() MyStack

* Initialize your data structure here.

func (*MyStack) Empty

func (this *MyStack) Empty() bool

* Returns whether the stack is empty.

func (*MyStack) Pop

func (this *MyStack) Pop() int

* Removes the element on top of the stack and returns that element.

func (*MyStack) Push

func (this *MyStack) Push(x int)

* Push element x onto stack.

func (*MyStack) Top

func (this *MyStack) Top() int

* Get the top element.