linked-list-cycle.go

// https://leetcode.com/problems/linked-list-cycle/
/**
 * Definition for singly-linked list.
 * type ListNode struct {
 *     Val int
 *     Next *ListNode
 * }
 */
func hasCycle(head *ListNode) bool {
    hare := head
    tortoise := head
    
    for hare != nil && hare.Next != nil {
        hare = hare.Next.Next
        tortoise = tortoise.Next
        
        if hare != nil && hare.Val == tortoise.Val {
            return true
        }
    }
    
    return false
}