Week08 作业

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

class Solution:
    def getIntersectionNode(self, headA: ListNode, headB: ListNode) -> ListNode:
        if not headA or not headB:
            return
        setA, setB = set(), set()
        while headA is not None:
            if headA not in setA:
                setA.add(headA)
            headA = headA.next
        while headB is not None:
            if headB in setA:
                return headB
            headB = headB.next
        return