Create: 206-Reverse-Linked-List.swift

swift/206-Reverse-Linked-List.swift

@@ -0,0 +1,28 @@
+/**
+ * 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 reverseList(_ head: ListNode?) -> ListNode? {
+ if (head === nil || head?.next === nil) {
+ return head
+ }
+
+ var prev: ListNode? = nil
+ var curr = head, next = curr?.next
+
+ while curr != nil {
+ next = curr?.next
+ curr?.next = prev
+ prev = curr
+ curr = next
+ }
+ return prev
+ }
+}