From af7c5dc109643a9d8ff0b06624e181ca7d0b7e36 Mon Sep 17 00:00:00 2001
From: reeseo3o <notyaeji@gmail.com>
Date: Sat, 18 Apr 2026 13:48:59 +0900
Subject: [PATCH] week7: reverse-linked-list

---
 reverse-linked-list/reeseo3o.js | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 reverse-linked-list/reeseo3o.js

diff --git a/reverse-linked-list/reeseo3o.js b/reverse-linked-list/reeseo3o.js
new file mode 100644
index 0000000000..4686b9fd54
--- /dev/null
+++ b/reverse-linked-list/reeseo3o.js
@@ -0,0 +1,28 @@
+// Time Complexity: O(n) - 노드를 한 번만 순회
+// Space Complexity: O(1) - 변수 3개(prev, current, next)만 사용
+const reverseList = (head) => {
+    let prev = null;
+    let current = head;
+
+    while (current !== null) {
+        const next = current.next;
+        current.next = prev;
+        prev = current;
+        current = next;
+    }
+
+    return prev;
+};
+
+// Time Complexity: O(n) - 노드 수만큼 재귀 호출
+// Space Complexity: O(n) - 콜 스택이 노드 수만큼 쌓임
+const reverseListRecursive = (head) => {
+    if (head === null || head.next === null) return head;
+
+    const newHead = reverseListRecursive(head.next);
+
+    head.next.next = head;
+    head.next = null;     
+
+    return newHead;
+};