LeetCode-面试题25-合并两个排序的链表

输入：1->2->4, 1->3->4
输出：1->1->2->3->4->4

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        if(l1==null)
            return l2;
        else if(l2==null)
            return l1;
        ListNode MergeHead = null;
        if(l1.val>l2.val){
            MergeHead = l2;
            MergeHead.next = mergeTwoLists(l1,l2.next);
        }
        else{
            MergeHead = l1;
            MergeHead.next = mergeTwoLists(l1.next,l2);
        }
        return MergeHead;
    }
}

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def mergeTwoLists(self, l1: ListNode, l2: ListNode) -> ListNode:
        if not l1: return l2
        elif not l2: return l1
        MergeHead = None
        if l1.val<l2.val:
            MergeHead = l1
            MergeHead.next = self.mergeTwoLists(l1.next,l2)
        else:
            MergeHead = l2
            MergeHead.next = self.mergeTwoLists(l1,l2.next)
        return MergeHead