From 9fac6a2738b1d5d1f65619bd23227ace0efb1f10 Mon Sep 17 00:00:00 2001
From: reeseo3o <notyaeji@gmail.com>
Date: Sat, 28 Mar 2026 00:25:56 +0900
Subject: [PATCH 1/3] week4: merge-two-sorted-lists

---
 merge-two-sorted-lists/reeseo3o.js | 42 ++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 merge-two-sorted-lists/reeseo3o.js

diff --git a/merge-two-sorted-lists/reeseo3o.js b/merge-two-sorted-lists/reeseo3o.js
new file mode 100644
index 0000000000..7b613d7802
--- /dev/null
+++ b/merge-two-sorted-lists/reeseo3o.js
@@ -0,0 +1,42 @@
+/**
+ * 1. Recursive approach
+ * Time complexity: O(n + m)
+ * Space complexity: O(n + m)
+ */
+// const mergeTwoLists = (list1, list2) => {
+//     if (!list1) return list2;
+//     if (!list2) return list1;
+//
+//     if (list1.val <= list2.val) {
+//         list1.next = mergeTwoLists(list1.next, list2);
+//         return list1;
+//     } else {
+//         list2.next = mergeTwoLists(list1, list2.next);
+//         return list2;
+//     }
+// };
+
+/**
+ * 2. Iterative approach + Dummy Node
+ * Time complexity: O(n + m)
+ * Space complexity: O(1)
+ */
+const mergeTwoLists = (list1, list2) => {
+    const dummy = new ListNode(-1);
+    let current = dummy;
+
+    while (list1 !== null && list2 !== null) {
+        if (list1.val <= list2.val) {
+            current.next = list1;
+            list1 = list1.next;
+        } else {
+            current.next = list2;
+            list2 = list2.next;
+        }
+        current = current.next;
+    }
+
+    current.next = list1 ?? list2;
+
+    return dummy.next;
+};

From 68408c98da1827dd472c7603d9e1b361f566b265 Mon Sep 17 00:00:00 2001
From: reeseo3o <notyaeji@gmail.com>
Date: Sat, 28 Mar 2026 18:37:38 +0900
Subject: [PATCH 2/3] week4: maximum-subarray

---
 maximum-subarray/reeseo3o.js | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 maximum-subarray/reeseo3o.js

diff --git a/maximum-subarray/reeseo3o.js b/maximum-subarray/reeseo3o.js
new file mode 100644
index 0000000000..a01f3711c5
--- /dev/null
+++ b/maximum-subarray/reeseo3o.js
@@ -0,0 +1,34 @@
+/**
+ * Time complexity: O(n)
+ * Space complexity: O(h) - h is the height of the tree, worst case O(n)
+ */
+const maxDepth = (root) => {
+  if (root === null) return 0;
+
+  const leftDepth = maxDepth(root.left);
+  const rightDepth = maxDepth(root.right);
+
+  return 1 + Math.max(leftDepth, rightDepth);
+};
+
+// BFS - TC: O(n) | SC: O(n)
+const maxDepthBFS = (root) => {
+  if (root === null) return 0;
+
+  const queue = [root];
+  let depth = 0;
+
+  while (queue.length > 0) {
+    const levelSize = queue.length;
+
+    for (let i = 0; i < levelSize; i++) {
+      const node = queue.shift();
+      if (node.left) queue.push(node.left);
+      if (node.right) queue.push(node.right);
+    }
+
+    depth++;
+  }
+
+  return depth;
+};

From fde6a4a74b5965d0bf91efe65a6cb6571dc5f1cd Mon Sep 17 00:00:00 2001
From: reeseo3o <notyaeji@gmail.com>
Date: Sat, 28 Mar 2026 18:40:24 +0900
Subject: [PATCH 3/3] docs: add complexity comments for maximum-subarray

---
 maximum-subarray/reeseo3o.js | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/maximum-subarray/reeseo3o.js b/maximum-subarray/reeseo3o.js
index a01f3711c5..1332a6f056 100644
--- a/maximum-subarray/reeseo3o.js
+++ b/maximum-subarray/reeseo3o.js
@@ -1,4 +1,5 @@
-/**
+/** 
+ * DFS
  * Time complexity: O(n)
  * Space complexity: O(h) - h is the height of the tree, worst case O(n)
  */
@@ -11,7 +12,11 @@ const maxDepth = (root) => {
   return 1 + Math.max(leftDepth, rightDepth);
 };
 
-// BFS - TC: O(n) | SC: O(n)
+/**
+ * BFS
+ * Time complexity: O(n)
+ * Space complexity: O(n)
+ */
 const maxDepthBFS = (root) => {
   if (root === null) return 0;