InsertionSortList.java

/*
 Author:     King, wangjingui@outlook.com
 Date:       Jan 02, 2015
 Problem:    Insertion Sort List
 Difficulty: Easy
 Source:     http://oj.leetcode.com/problems/insertion-sort-list/
 Notes:
 Sort a linked list using insertion sort.

 Solution: ...
*/
/**
 * 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 || head.next == null) return head;
        ListNode dummy = new ListNode(Integer.MIN_VALUE);
        dummy.next = head;
        ListNode cur = head.next;
        head.next = null;
        while (cur != null) {
            ListNode tmp = dummy;
            while (tmp.next != null && tmp.next.val <= cur.val) tmp = tmp.next;
            ListNode next = cur.next;
            cur.next = tmp.next;
            tmp.next = cur;
            cur = next;
        }
        return dummy.next;
    }
}