HTMLify

/**
 * Definition for singly-linked list.
 * type ListNode struct {
 *     Val int
 *     Next *ListNode
 * }
 */

func contain(node_list []*ListNode, node *ListNode) bool {
	for _, n := range node_list {
		if n == node {
			return true
		}
	}
	return false
}

func hasCycle(head *ListNode) bool {
	var seen_nodes []*ListNode
	for head!=nil {
		if contain(seen_nodes, head) {
			return true
		}
		seen_nodes = append(seen_nodes, head)
		head = head.Next
	}
	return false
}