leetcode——23. 合并K个排序链表

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

class Solution(object):
    def mergeKLists(self, lists):
        """
        :type lists: List[ListNode]
        :rtype: ListNode
        """
        if not lists:
            return 
        #暴力法
        r=[]
        for i in range(len(lists)):
            if not lists[i]:
                continue
            head=lists[i]
            p=head
            while p:
                r.append(p.val)
                p=p.next
        if not r:
            return
        r.sort()
        head=ListNode(r[0])
        p=head
        for j in range(1,len(r)):
            p.next=ListNode(r[j])
            p=p.next
        return head