LeetCode 链表的插入排序

Sort a linked list using insertion sort

创建一个新的链表，将旧链表的节点插入到正确的位置

package cn.edu.algorithm.huawei;

public class Solution {
    public ListNode insertionSortList(ListNode head) {
        //哑节点
        ListNode dumy = new ListNode(Integer.MIN_VALUE);
        ListNode cur = head;
        ListNode pre = dumy;
        while (cur != null) {
            //保存当前节点下一个节点
            ListNode next = cur.next;
            pre = dumy;
            //寻找当前节点正确位置的一个节点
            while (pre.next != null && pre.next.val < cur.val) {
                pre = pre.next;
            }
            //将当前节点加入新链表中
            cur.next = pre.next;//指向插入位置后面的节点
            ListNode test = cur.next;

            pre.next = cur;
            //处理下一个节点
            cur = next;
        }
        return dumy.next;
    }

    public static void main(String[] args) {
        ListNode head = new ListNode(2);
        head.next = new ListNode(1);
        Solution solution = new Solution();
        ListNode list = solution.insertionSortList(head);
        while (list != null) {
            System.out.println(list.val);
            list = list.next;
        }
    }
}

class ListNode {
    int val;
    ListNode next;

    ListNode(int x) {
        val = x;
        next = null;
    }

    @Override
    public String toString() {
        return val + "";
    }
}