package algorithm.stack;

import java.util.Stack;

/**

* @Author: ChangXuan

* @Decription: 实现一个特殊的栈，在实现栈的基本功能的基础上，再实现返回栈中最小元素的操作

* @Date: 12:45 2020/6/19

**/

public class MyStack1 {

private Stack<Integer> stackData;

private Stack<Integer> stackMin;

public MyStack1() {

this.stackData = new Stack<Integer>();

this.stackMin = new Stack<Integer>();

}

public void push(Integer newNum){

this.stackData.push(newNum);

if (this.stackMin.isEmpty() || newNum <= this.getMin()){

this.stackMin.push(newNum);

}

}

public Integer pop(){

if (this.stackData.isEmpty()){

throw new RuntimeException("Stack is empty");

}

Integer value = this.stackData.pop();

if (value.equals(this.getMin())){

this.stackMin.pop();

}

return value;

}

public Integer getMin(){

if (this.stackMin.isEmpty()){

throw new RuntimeException("Yous stack is empty");

}

return this.stackMin.peek();

}

}