package main

import (
    "fmt"
)

type Node {
    value string
    next *Node
}

func HasCycleNode(root *Node) bool {
    if root == nil {
        return false
    }
    current, ahead := root, root
    for ahead != nil && ahead.next != nil {
        current = root.next
        ahead = root.next.next
        if slow === ahead {
            return true
        }
    }
    return false
}

func main() {
    node1 := &Node{ value: "A" }
    node2 := &Node{ value: "B" }
    node3 := &Node{ value: "C" }
    node4 := &Node{ value: "D" }

    node1.next  = node2
    node4.next  = node3
    node3.next  = node4

    fmt.Println("Cycle node:", HasCycleNodes(node1))
}