Create: 19-Remove-Nth-Node-From-End-of-List.swift

nick322 · Sep 19, 2022 · 8db7e1e · 8db7e1e
1 parent f0c76fb
commit 8db7e1e
Showing 1 changed file with 31 additions and 0 deletions.
diff --git a/swift/19-Remove-Nth-Node-From-End-of-List.swift b/swift/19-Remove-Nth-Node-From-End-of-List.swift
@@ -0,0 +1,31 @@
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ * public var val: Int
+ * public var next: ListNode?
+ * public init() { self.val = 0; self.next = nil; }
+ * public init(_ val: Int) { self.val = val; self.next = nil; }
+ * public init(_ val: Int, _ next: ListNode?) { self.val = val; self.next = next; }
+ * }
+ */
+class Solution {
+ func removeNthFromEnd(_ head: ListNode?, _ n: Int) -> ListNode? {
+ if head === nil {
+ return head
+ }
+ var slow = head, fast = head
+ for i in 1...n + 1 {
+ if (slow === nil) {
+ return head?.next
+ }
+ slow = slow?.next
+ }
+
+ while slow != nil {
+ slow = slow?.next
+ fast = fast?.next
+ }
+ fast?.next = fast?.next?.next
+ return head
+ }
+}