[数据结构与算法]剑指offer 06 从尾到头打印链表 Kotlin

一、题目描述

输入一个链表的头节点，从尾到头反过来返回每个节点的值（用数组返回）。

示例 1：

输入：head = [1,3,2]
输出：[2,3,1]

限制：

0 <= 链表长度 <= 10000

二、代码

/**
 * Example:
 * var li = ListNode(5)
 * var v = li.`val`
 * Definition for singly-linked list.
 * class ListNode(var `val`: Int) {
 *     var next: ListNode? = null
 * }
 */
class Solution {
    fun reversePrint(head: ListNode?): IntArray {
        val stack = Stack<Int>()
        var p = head
        while(p != null){
            stack.push(p.`val`)
            p = p.next
        }
        val result = IntArray(stack.size)
        for(index in result.indices){
            result[index] = stack.pop()
        }
        return result
    }

}

附一个大佬的解法

class Solution {
    fun reversePrint(head: ListNode?): IntArray {
        var curNode = head
        var count = 0
        while (curNode != null) {
            curNode = curNode?.next
            count++
        }

        val result = IntArray(count)
        curNode = head
        var index = count - 1
        while (curNode != null) {
            result[index] = curNode!!.`val`
            curNode = curNode?.next
            index--
        }

        return result
    }
}

三、题目合集

点这里~