interviewbit-heaps-and-maps-merge-k-sorted-lists.py

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

class Solution:
    # @param A : list of linked list
    # @return the head node in the linked list
    def mergeKLists(self, A):
        nodes = []
        for node in A:
            current = node
            while current:
                nodes.append(current)
                current = current.next

        nodes.sort(key=lambda x: x.val)
        for i in range(len(nodes) - 1):
            nodes[i].next = nodes[i + 1]

        nodes[-1].next = None

        return nodes[0]