[LeetCode][Python3] 142. Linked List Cycle II

Problem :

https://leetcode.com/problems/linked-list-cycle-ii/

My Solution :

# Definition for singly-linked list.

# class ListNode:

#     def __init__(self, x):

#         self.val = x

#         self.next = None

class Solution:

    def detectCycle(self, head):

        p1 = p2 = head

        while True:

            try:

                p1 = p1.next

                p2 = p2.next.next

            except:

                return

            if p1 is p2:

                p2 = head

                while p1 is not p2:

                    p1 = p1.next

                    p2 = p2.next

                return p1

Comment :

예전에 풀었던 문제와 같은 원리로 접근하였다. 토끼와 거북이 알고리즘.

https://en.wikipedia.org/wiki/Cycle_detection

2019/01/25 - [프로그래밍/LeetCode] - [LeetCode][Python3] 287. Find the Duplicate Number