package algorithm.stack;

import algorithm.list.Node;

/**

* @ClassName Stack

* @Description 链栈

* @Author changxuan

* @Date 2020/6/23 下午8:05

**/

public class Stack {

Node top;

/**

* 出栈

* @return 栈顶元素

*/

int pop(){

if (top == null){

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

}

int item = top.data;

top = top.next;

return item;

}

/**

* 入栈

*/

void push(int data){

Node node = new Node(data);

node.next = top;

top = node;

}

int peek(){

if (top == null){

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

}

return this.top.data;

}

Boolean isEmpty(){

return top == null ? true : false;

}

void sort(){

Stack help = new Stack();

while (!this.isEmpty()){

int cur = this.pop();

while (!help.isEmpty() && help.peek()<cur){

this.push(help.pop());

}

help.push(cur);

}

while (!help.isEmpty()){

this.push(help.pop());

}

}

}