LeetCode

题目：

Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.

思路：

不断选取较小的元素，当一个链表为空时，则直接链接到下一个链表。

package list;

public class MergeTwoSortedLists {

    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {        
        ListNode p = new ListNode(0);
        p.next = null;
        ListNode head = p;
        
        while (l1 != null && l2 != null) {
            if (l1.val < l2.val) {
                p.next = l1;
                l1 = l1.next;
            } else {
                p.next = l2;
                l2 = l2.next;
            }
            p = p.next;
        }
        
        p.next = l1 == null ? l2 : l1;
        return head.next;
    }
    
    public static void main(String[] args) {
        // TODO Auto-generated method stub

    }

}