Feat: 206. Reverse Linked List

Author: HC-kang

reverse-linked-list/HC-kang.ts

@@ -0,0 +1,25 @@
+class ListNode {
+  val: number;
+  next: ListNode | null;
+  constructor(val?: number, next?: ListNode | null) {
+    this.val = val === undefined ? 0 : val;
+    this.next = next === undefined ? null : next;
+  }
+}
+
+/**
+ * https://leetcode.com/problems/reverse-linked-list
+ * T.C. O(n)
+ * S.C. O(1)
+ */
+function reverseList(head: ListNode | null): ListNode | null {
+  let prev: ListNode | null = null;
+  let current: ListNode | null = head;
+  while (current !== null) {
+    const next = current.next;
+    current.next = prev;
+    prev = current;
+    current = next;
+  }
+  return prev;
+}