题解 | #合并两个排序的链表#

# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param pHead1 ListNode类 
# @param pHead2 ListNode类 
# @return ListNode类
#
class Solution:
    def Merge(self , pHead1: ListNode, pHead2: ListNode) -> ListNode:
        if not pHead1 or not pHead2:
            return pHead1 or pHead2
        if pHead1.val >= pHead2.val:
            bigger_node = pHead1
            smaller_node = pHead2
        else:
            bigger_node = pHead2
            smaller_node = pHead1
        pre1, cur1 = None, smaller_node
        pre2, cur2 = None, bigger_node
        while cur1 and cur2:
            while cur2 and cur1 and cur2.val >= cur1.val and (cur1.next and cur2.val <= cur1.next.val):
                cur1_next = cur1.next
                cur1.next = cur2
                cur2_next = cur2.next
                cur2.next = cur1_next
                cur1 = cur1.next
                cur2 = cur2_next
            if cur2 and cur1 and cur2.val >= cur1.val and not cur1.next:
                cur1.next = cur2
                break
            cur1 = cur1.next
        return smaller_node