[week2] solve 206. Reverse Linked List

Author: bky373

reverse-linked-list/bky373.java

@@ -0,0 +1,21 @@
+/**
+ * https://leetcode.com/problems/reverse-linked-list/
+ * TC: O(N)
+ * SC: O(N)
+ */
+class Solution_206 {
+
+    public ListNode reverseList(ListNode head) {
+        if (head == null) {
+            return head;
+        }
+        ListNode a = new ListNode(head.val);
+        ListNode b;
+        while (head.next != null) {
+            b = new ListNode(head.next.val, a);
+            a = b;
+            head = head.next;
+        }
+        return a;
+    }
+}