LeetCode删除排序链表中的重复元素Swift

给定一个排序链表，删除所有重复的元素，使得每个元素只出现一次。

示例 1:

输入: 1->1->2
输出: 1->2

示例 2:

输入: 1->1->2->3->3
输出: 1->2->3

思路：如果当前结点值==下一结点值，就把当前结点的next指向下下结点。

/**
 * 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 deleteDuplicates(_ head: ListNode?) -> ListNode? {
        var current = head
        while nil != current && nil != current?.next {
            if current?.val == current?.next?.val {
                current?.next = current?.next?.next
            }else{
                current = current?.next
            }
        }
        return head
    }
}