package jiuzhang.java.elementary;

import java.util.Stack;

//Implement Queue by Two Stacks

public class MyQueue {

private Stack<Integer> stack1;

private Stack<Integer> stack2;

public MyQueue() {

// do initialization if necessary

stack1 = new Stack<Integer>();

stack2 = new Stack<Integer>();

}

/*

* @param element: An integer

* @return: nothing

*/

public void push(int element) { //必须理解本质，而不仅仅是顺序步骤操作,本质是倒到有一个stack为空的时候在另一个顶端操作

// write your code here

while (!stack2.empty()) {

stack1.push(stack2.pop());

}

stack1.push(element);

}

/*

* @return: An integer

*/

public int pop() {

// write your code here

while (!stack1.empty()) {

stack2.push(stack1.pop());

}

return stack2.pop();

}

/*

* @return: An integer

*/

public int top() {

// write your code here

while (!stack1.empty()) {

stack2.push(stack1.pop());

}

return stack2.peek();

}

}