Java [Leetcode 232]implement Queue using Stacks

Title Description:

Implement the following operations of a queue using stacks.

• Push (x)--push element x to the back of the queue.
• Pop ()--Removes the element from in front of the queue.
• Peek ()--Get the front element.
• Empty ()--Return whether the queue is empty.

Notes:

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

Problem Solving Ideas:

Using two stacks, one for inserting data and the other for outputting data.

The code is as follows:

Class Myqueue {    stack<integer> input = new stack<integer> ();    stack<integer> output = new stack<integer> ();    Push element x to the back of the queue.    public void push (int x) {        input.push (x);    }    Removes the element from in front of the queue.    public void Pop () {        peek ();        Output.pop ();    }    Get the front element.    public int Peek () {        if (Output.empty ()) {"            while (!input.empty ()) {                Output.push (Input.pop ())            }        }}        return Output.peek ();    }    Return whether the queue is empty.    public Boolean empty () {        return input.empty () && output.empty ();}    }

　　

Java [Leetcode 232]implement Queue using Stacks