[Swift]LeetCode82. 删除排序链表中的重复元素 II | Remove Duplicates from Sorted List II
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Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.
Example 1:
Input: 1->2->3->3->4->4->5 Output: 1->2->5
Example 2:
Input: 1->1->1->2->3 Output: 2->3
给定一个排序链表，删除所有含有重复数字的节点，只保留原始链表中 没有重复出现 的数字。
示例 1:
输入: 1->2->3->3->4->4->5 输出: 1->2->5
示例 2:
输入: 1->1->1->2->3 输出: 2->3
28ms
1 class Solution {
2 func deleteDuplicates(_ head: ListNode?) -> ListNode? {
3 var node = head
4 var result: ListNode? = nil
5 var prevNode: ListNode? = nil
6 while node != nil {
7 var next = node!.next
8 if next != nil && next!.val == node!.val {
9 while next != nil && next!.val == node!.val {
10 next = next!.next
11 }
12 if prevNode != nil {
13 prevNode!.next = next
14 } else {
15 if result == nil { result = prevNode }
16 }
17 node = next
18 } else {
19 prevNode = node
20 if result == nil { result = prevNode }
21 node = next
22 }
23 }
24 return result
25 }
26 }32ms
1 /**
2 * Definition for singly-linked list.
3 * public class ListNode {
4 * public var val: Int
5 * public var next: ListNode?
6 * public init(_ val: Int) {
7 * self.val = val
8 * self.next = nil
9 * }
10 * }
11 */
12 class Solution {
13 func deleteDuplicates(_ head: ListNode?) -> ListNode? {
14 let dummyHead = ListNode(0)
15 dummyHead.next = head
16 var previous: ListNode? = dummyHead
17 var current = previous
18
19 while current != nil {
20 while current?.next != nil && previous?.next?.val == current?.next?.val {
21 current = current?.next
22 }
23
24 if previous?.next === current {
25 previous = previous?.next
26 } else {
27 previous?.next = current?.next
28 }
29 current = current?.next
30 }
31
32 return dummyHead.next
33 }
34 }44ms
1 /**
2 * Definition for singly-linked list.
3 * public class ListNode {
4 * public var val: Int
5 * public var next: ListNode?
6 * public init(_ val: Int) {
7 * self.val = val
8 * self.next = nil
9 * }
10 * }
11 */
12 class Solution {
13 func deleteDuplicates(_ head: ListNode?) -> ListNode? {
14 let root = ListNode(-1)
15 root.next = head
16 var node: ListNode? = root
17 while node?.next != nil {
18 if node?.next?.val == node?.next?.next?.val {
19 let val = node?.next?.val
20 while node?.next != nil && node?.next?.val == val {
21 node?.next = node?.next?.next
22 }
23 } else {
24 node = node?.next
25 }
26 }
27 return root.next
28 }
29 }76ms
1 /**
2 * Definition for singly-linked list.
3 * public class ListNode {
4 * public var val: Int
5 * public var next: ListNode?
6 * public init(_ val: Int) {
7 * self.val = val
8 * self.next = nil
9 * }
10 * }
11 */
12 class Solution {
13 func deleteDuplicates(_ head: ListNode?) -> ListNode? {
14 if head == nil {
15 return head
16 }
17 let dummy:ListNode? = ListNode(0)
18 dummy?.next = head
19 var pre = dummy
20 while pre?.next != nil {
21 var same = false
22 var node = pre?.next
23 while node?.next != nil && node!.val == node?.next!.val {
24 node = node?.next
25 same = true
26 }
27 if same {
28 pre?.next = node?.next
29 } else {
30 pre = pre?.next
31 }
32 }
33 return dummy?.next
34 }
35 }