java-66-用递归颠倒一个栈。例如输入栈{1,2,3,4,5}，1在栈顶。颠倒之后的栈为{5,4,3,2,1}，5处在栈顶

import java.util.Stack;public class ReverseStackRecursive {/** * Q 66.颠倒栈。 * 题目：用递归颠倒一个栈。例如输入栈{1,2,3,4,5}，1在栈顶。 * 颠倒之后的栈为{5,4,3,2,1}，5处在栈顶。 *1. Pop the top element *2. Reverse the remaining stack *3. Add the top element to the bottom of the remaining stack */public static void main(String[] args) {ReverseStackRecursive r=new ReverseStackRecursive();Stack<Integer> stack=new Stack<Integer>();for(int i=0;i<10;i++){stack.add(i);}r.printStack(stack);r.reverseStack(stack);r.printStack(stack);}public void reverseStack(Stack<Integer> stack){if(!stack.empty()){Integer top=stack.pop();reverseStack(stack);addToBottom(stack,top);}}public void addToBottom(Stack<Integer> stack,Integer ele){if(stack.empty()){stack.push(ele);}else{Integer top=stack.pop();addToBottom(stack,ele);//importantstack.push(top);}}public void printStack(Stack<Integer> stack){/*while(!stack.empty()){System.out.print(stack.pop()+",");}*///we don't remove the elements in the stack.for(Integer x:stack){System.out.print(x+",");}System.out.println();}}