🌵141. Linked List Cycle
https://leetcode.com/problems/linked-list-cycle/
js
/**
* Definition for singly-linked list.
* function ListNode(val) {
* this.val = val;
* this.next = null;
* }
*/
/**
* @param {ListNode} head
* @return {boolean}
*/
var hasCycle = function(head) {
let l1 = new ListNode()
let l2 = new ListNode()
l1.next = l2.next = head
while (l1 !== l2) {
if (!l1 || !l2 || !l2.next) {
return false
}
l1 = l1.next
l2 = l2.next.next
}
return true
}py
# Definition for singly-linked list.
# class ListNode(object):
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution(object):
def hasCycle(self, head):
"""
:type head: ListNode
:rtype: bool
"""
l1 = ListNode(None)
l2 = ListNode(None)
l1.next = l2.next = head
while l1 != l2:
if not l1 or not l2 or not l2.next:
return False
l1 = l1.next
l2 = l2.next.next
return True