数据结构算法操作试题(C++/Python)——合并K个排序链表

class Solution(object):
    def mergeKLists(self, lists):
        """
        :type lists: List[ListNode]
        :rtype: ListNode
        """
        valsList = []
        for nodeItem in lists:
            while nodeItem:
                valsList.append(nodeItem.val)
                nodeItem = nodeItem.next
        if not valsList: return None
        else: valsList.sort()
        head = ListNode(0)
        tmp_p = head
        for valItem in valsList:
            tmp_p.next = ListNode(valItem)
            tmp_p = tmp_p.next
        return head.next