使用插入排序算法對列表進行排序——Leetcode系列（五）

Sort a linked list using insertion sort.

My Answer:

<span style="font-size:14px;">/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
public class Solution {
    public ListNode insertionSortList(ListNode head) {
        if(head == null){
            return head;
        }
        ListNode pivot = head.next;
        ListNode newHead = head;
        newHead.next = null;
        while(pivot != null){
            ListNode newPivot = newHead;
            ListNode pre = newPivot;
            while(newPivot != null){
                if(pivot.val <= newPivot.val){
                    ListNode temp = pivot.next;
                    if(newHead == newPivot){
                        pivot.next = newHead;
                        newHead = pivot;
                    }else{
                        pivot.next = pre.next;
                        pre.next = pivot;
                    }
                    pivot = temp;
                    break;
                }
                pre = newPivot;
                newPivot = newPivot.next;
            }
            if(newPivot == null){
                pre.next = pivot;
                pivot = pivot.next;
                pre.next.next = null;
            }
        }
        return newHead;
    }
}</span>

題目來源： https://oj.leetcode.com/problems/insertion-sort-list/