ReverseLinkedList.swift

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// Reverse a singly linked list.

// Example:

// Input: 1->2->3->4->5->NULL
// Output: 5->4->3->2->1->NULL
// Follow up:

// A linked list can be reversed either iteratively or recursively. Could you implement both?


/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     public var val: Int
 *     public var next: ListNode?
 *     public init(_ val: Int) {
 *         self.val = val
 *         self.next = nil
 *     }
 * }
 */
class Solution {
    func reverseList(_ head: ListNode?) -> ListNode? {
        
    }
}