142. Linked List Cycle II

[개발뉴비(coderhs)]

class Solution:

    def __init__(self):

        self.ll = []

        self.id = {}

    def detectCycle(self, head: Optional[ListNode]) -> Optional[ListNode]:

        key = id(head)

        if head == None:

            return None

        if key in self.id:

            return self.ll[self.id[key]]

        self.id[key] = len(self.ll)

        self.ll.append(head)

        return self.detectCycle(head.next)

그냥 1초도 고민하기가 싫어서 걍 풀었음