_1265.java

package com.fishercoder.solutions;

import java.util.Stack;

/**
 * 1265. Print Immutable Linked List in Reverse
 *
 * You are given an immutable linked list, print out all values of each node in reverse with the help of the following interface:
 * ImmutableListNode: An interface of immutable linked list, you are given the head of the list.
 * You need to use the following functions to access the linked list (you can't access the ImmutableListNode directly):
 * ImmutableListNode.printValue(): Print value of the current node.
 * ImmutableListNode.getNext(): Return the next node.
 * The input is only given to initialize the linked list internally.
 * You must solve this problem without modifying the linked list. In other words, you must operate the linked list using only the mentioned APIs.
 *
 * Follow up:
 * Could you solve this problem in:
 * Constant space complexity?
 * Linear time complexity and less than linear space complexity?
 *
 * Example 1:
 * Input: head = [1,2,3,4]
 * Output: [4,3,2,1]
 *
 * Example 2:
 * Input: head = [0,-4,-1,3,-5]
 * Output: [-5,3,-1,-4,0]
 *
 * Example 3:
 * Input: head = [-2,0,6,4,4,-6]
 * Output: [-6,4,4,6,0,-2]
 *
 * Constraints:
 * The length of the linked list is between [1, 1000].
 * The value of each node in the linked list is between [-1000, 1000].
 * */
public class _1265 {

    interface ImmutableListNode {
        ImmutableListNode getNext();

        void printValue();
    }

    public static class Solution1 {
        public void printLinkedListInReverse(ImmutableListNode head) {
            Stack<ImmutableListNode> stack = new Stack();
            while (head != null) {
                stack.add(head);
                head = head.getNext();
            }
            while (!stack.isEmpty()) {
                head = stack.pop();
                head.printValue();
            }
        }
    }
}