LeetCode之Insertion Sort List（Kotlin）

問題： Sort a linked list using insertion sort.

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
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方法： 建立list保存全部節點，而後對list作直接插入排序，不變化node的位置，只修改node的value，排序後清空list，最後輸出頭節點即爲結果。

具體實現：

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>) {

}
複製代碼

有問題隨時溝通

具體代碼實現能夠參考Github