package algorithm.stack;

import java.util.Stack;

/**

* @Author: ChangXuan

* @Decription: 逆序栈

* @Date: 12:26 2020/6/22

**/

public class ReverseStack {

public static void main(String[] args) {

Stack<Integer> stack = new Stack<>();

stack.push(1);

stack.push(2);

stack.push(3);

stack.push(4);

stack.push(5);

System.out.println("逆序前：");

for (Integer item : stack){

System.out.println(item);

}

reverse(stack);

System.out.println("逆序后：");

for (Integer item : stack){

System.out.println(item);

}

}

/**

* 取出栈底元素

* @param stack 栈

* @return 栈底元素

*/

public static int getAndRemoveLastElement(Stack<Integer> stack){

int result = stack.pop();

if (stack.isEmpty()){

return result;

}else {

int last = getAndRemoveLastElement(stack);

stack.push(result);

return last;

}

}

public static void reverse(Stack<Integer> stack){

if (stack.isEmpty()){

return;

}

int i = getAndRemoveLastElement(stack);

reverse(stack);

stack.push(i);

}

}