Function reverseList1

reverse_linked_list_206/solution.go:34–57

Reverses the passed list without creating a new list by prepending front nodes to the end.

(head *ListNode)

// Reverses the passed list without creating a new list by
// prepending front nodes to the end.
func reverseList1(head *ListNode) *ListNode {
	if head == nil {
		return nil
	}

	// find the end of the list
	end := head
	for end.Next != nil {
		end = end.Next
	}

	// prepend every front node to the end
	// 1,2,3
	// 2,3,1
	// 3,2,1
	for end != head {
		hold := head
		head = head.Next
		hold.Next = end.Next
		end.Next = hold
	}

	return head
}