Insertion Sort List

Sort a linked list using insertion sort.

Example

Given 1->3->2->0->null, return 0->1->2->3->null.

分析：

利用insertion sort的原理，把list A的一个node插入到另一个list B里面，这里关键是list B的尾部的处理。

/**
 * Definition for ListNode.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int val) {
 *         this.val = val;
 *         this.next = null;
 *     }
 * }
 */ 
public class Solution {
    /**
     * @param head: The first node of linked list.
     * @return: The head of linked list.
     * cnblogs.com/beiyeqingteng/
     */
     
    public ListNode insertionSortList(ListNode head) {
        if (head == null || head.next == null) return head;
        ListNode dummyNode = new ListNode(Integer.MIN_VALUE);  // a new list
        
        while(head != null) {
            ListNode current = dummyNode;
            while(head.val > current.val && current.next != null && current.next.val < head.val) {
                current = current.next;
            }
            ListNode next = current.next;
            current.next = head;
            head = head.next;
            current.next.next = next;
        }
        return dummyNode.next;
    }
}

转载请注明出处：cnblogs.com/beiyeqingteng/