LeetCode之Insertion Sort List（Kot

问题：
Sort a linked list using insertion sort.

image

A graphical example of insertion sort. The partial sorted list (black) initially contains only the first element in the list.
With each iteration one element (red) is removed from the input data and inserted in-place into the sorted list

Algorithm of Insertion Sort:
1. Insertion sort iterates, consuming one input element each repetition, and growing a sorted output list.
2. At each iteration, insertion sort removes one element from the input data, finds the location it belongs within the sorted list, and inserts it there.
3. It repeats until no input elements remain.

Example 1:

Input: 4->2->1->3
Output: 1->2->3->4
Example 2:

Input: -1->5->3->4->0
Output: -1->0->3->4->5

方法：
创建list保存所有节点，然后对list做直接插入排序，不变化node的位置，只修改node的value，排序后清空list，最后输出头节点即为结果。

具体实现：

class InsertionSortList {
    // Definition for singly-linked list.
    class ListNode(var `val`: Int) {
        var next: ListNode? = null
    }

    private val list = mutableListOf<ListNode>()

    fun insertionSortList(head: ListNode?): ListNode? {
        var curNode = head
        while (curNode != null) {
            list.add(curNode)
            curNode = curNode.next
        }
        for (index in list.indices) {
            var j = index
            val num = list[index].`val`
            while (j > 0 && num < list[j - 1].`val`) {
                list[j].`val` = list[j - 1].`val`
                j--
            }
            list[j].`val` = num
        }
        list.clear()
        return head
    }
}

fun main(args: Array<String>) {

}

有问题随时沟通

具体代码实现可以参考Github