From 28866eb83303fcf07c85bc01f04eae814240c31b Mon Sep 17 00:00:00 2001
From: Yuseok Jo <yuseok89@gmail.com>
Date: Sat, 19 Sep 2026 01:24:37 +0900
Subject: [PATCH 1/6] lowest common ancestor of a binary search tree solution

---
 .../yuseok89.py                                | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
 create mode 100644 lowest-common-ancestor-of-a-binary-search-tree/yuseok89.py

diff --git a/lowest-common-ancestor-of-a-binary-search-tree/yuseok89.py b/lowest-common-ancestor-of-a-binary-search-tree/yuseok89.py
new file mode 100644
index 0000000000..9441d2c685
--- /dev/null
+++ b/lowest-common-ancestor-of-a-binary-search-tree/yuseok89.py
@@ -0,0 +1,18 @@
+# TC: O(H)
+# SC: O(1)
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+class Solution:
+    def lowestCommonAncestor(self, root: 'TreeNode', p: 'TreeNode', q: 'TreeNode') -> 'TreeNode':
+        if root.val < p.val and root.val < q.val:
+            return self.lowestCommonAncestor(root.right, p, q)
+        elif root.val > p.val and root.val > q.val:
+            return self.lowestCommonAncestor(root.left, p, q)
+        else:
+            return root
+

From 46c37b9945d997bf8db3bdfbdb8727b35edbb388 Mon Sep 17 00:00:00 2001
From: Yuseok Jo <yuseok89@gmail.com>
Date: Sat, 19 Sep 2026 01:28:52 +0900
Subject: [PATCH 2/6] kth smallest element in a bst solution

---
 kth-smallest-element-in-a-bst/yuseok89.py | 32 +++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 kth-smallest-element-in-a-bst/yuseok89.py

diff --git a/kth-smallest-element-in-a-bst/yuseok89.py b/kth-smallest-element-in-a-bst/yuseok89.py
new file mode 100644
index 0000000000..39ddefdce3
--- /dev/null
+++ b/kth-smallest-element-in-a-bst/yuseok89.py
@@ -0,0 +1,32 @@
+# TC: O(N)
+# SC: O(1)
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
+class Solution:
+    def kthSmallest(self, root: TreeNode | None, k: int) -> int:
+
+        ans = 0
+
+        def rec(node: TreeNode | None) -> None:
+            nonlocal k, ans
+
+            if node is None or k <= 0:
+                return
+
+            rec(node.left)
+
+            k -= 1
+            if k == 0:
+                ans = node.val
+                return
+
+            rec(node.right)
+
+        rec(root)
+
+        return ans
+

From e9a16d7f96733fbfcf193987bc7c719589365756 Mon Sep 17 00:00:00 2001
From: Yuseok Jo <yuseok89@gmail.com>
Date: Sat, 19 Sep 2026 01:31:45 +0900
Subject: [PATCH 3/6] insert interval solution

---
 insert-interval/yuseok89.py | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 insert-interval/yuseok89.py

diff --git a/insert-interval/yuseok89.py b/insert-interval/yuseok89.py
new file mode 100644
index 0000000000..a5184096af
--- /dev/null
+++ b/insert-interval/yuseok89.py
@@ -0,0 +1,24 @@
+#TD: O(1)
+#SC: O(2)
+class Solution:
+    def insert(self, intervals: list[list[int]], newInterval: list[int]) -> list[list[int]]:
+
+        ans = []
+        is_processed = False
+
+        for interval in intervals:
+            if is_processed or interval[1] < newInterval[0]:
+                ans.append(interval)
+            elif newInterval[1] < interval[0]:
+                ans.append(newInterval)
+                ans.append(interval)
+                is_processed = True
+            else:
+                newInterval[0] = min(newInterval[0], interval[0])
+                newInterval[1] = max(newInterval[1], interval[1])
+
+        if not ans or ans[-1][1] < newInterval[0]:
+            ans.append(newInterval)
+
+        return ans
+

From 4a5585d75c43d8e75fc86b5ca245637efbd46d02 Mon Sep 17 00:00:00 2001
From: Yuseok Jo <yuseok89@gmail.com>
Date: Sat, 19 Sep 2026 01:34:28 +0900
Subject: [PATCH 4/6] find median from data atream solution

---
 find-median-from-data-stream/yuseok89.py | 49 ++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 find-median-from-data-stream/yuseok89.py

diff --git a/find-median-from-data-stream/yuseok89.py b/find-median-from-data-stream/yuseok89.py
new file mode 100644
index 0000000000..70cf0d84f1
--- /dev/null
+++ b/find-median-from-data-stream/yuseok89.py
@@ -0,0 +1,49 @@
+# TC (NlogN)
+# SC (N)
+class MedianFinder:
+
+    def __init__(self):
+        self.max_heap = []
+        self.min_heap = []
+
+    def addNum(self, num: int) -> None:
+        if len(self.min_heap) == 0 and len(self.max_heap) == 0:
+            heapq.heappush(self.min_heap, num)
+        elif len(self.max_heap) == 0:
+            mid = heapq.heappop(self.min_heap)
+            heapq.heappush(self.max_heap, -min(mid, num))
+            heapq.heappush(self.min_heap, max(mid, num))
+        elif len(self.max_heap) == len(self.min_heap):
+            mid1 = -self.max_heap[0]
+            mid2 = self.min_heap[0]
+
+            if num <= mid1:
+                heapq.heappush(self.max_heap, -num)
+            else:
+                heapq.heappush(self.min_heap, num)
+        else:
+            if len(self.max_heap) > len(self.min_heap):
+                mid = -heapq.heappop(self.max_heap)
+            else:
+                mid = heapq.heappop(self.min_heap)
+
+            heapq.heappush(self.max_heap, -min(mid, num))
+            heapq.heappush(self.min_heap, max(mid, num))
+
+    def findMedian(self) -> float:
+        if len(self.max_heap) == len(self.min_heap):
+            mid1 = -self.max_heap[0]
+            mid2 = self.min_heap[0]
+            return (mid1 + mid2) / 2.0
+        else:
+            if len(self.max_heap) > len(self.min_heap):
+                return float(-self.max_heap[0])
+            else:
+                return float(self.min_heap[0])
+
+
+# Your MedianFinder object will be instantiated and called as such:
+# obj = MedianFinder()
+# obj.addNum(num)
+# param_2 = obj.findMedian()
+

From f42006c70b323b5db5cb55fc7f3147d9396cce14 Mon Sep 17 00:00:00 2001
From: Yuseok Jo <yuseok89@gmail.com>
Date: Sat, 19 Sep 2026 20:44:17 +0900
Subject: [PATCH 5/6] =?UTF-8?q?=EB=A6=AC=EB=B7=B0=20=EB=B0=98=EC=98=81?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 insert-interval/yuseok89.py                                | 2 +-
 lowest-common-ancestor-of-a-binary-search-tree/yuseok89.py | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/insert-interval/yuseok89.py b/insert-interval/yuseok89.py
index a5184096af..1a94271d4d 100644
--- a/insert-interval/yuseok89.py
+++ b/insert-interval/yuseok89.py
@@ -1,4 +1,4 @@
-#TD: O(1)
+#TC: O(1)
 #SC: O(2)
 class Solution:
     def insert(self, intervals: list[list[int]], newInterval: list[int]) -> list[list[int]]:
diff --git a/lowest-common-ancestor-of-a-binary-search-tree/yuseok89.py b/lowest-common-ancestor-of-a-binary-search-tree/yuseok89.py
index 9441d2c685..ddb2b8ae59 100644
--- a/lowest-common-ancestor-of-a-binary-search-tree/yuseok89.py
+++ b/lowest-common-ancestor-of-a-binary-search-tree/yuseok89.py
@@ -1,5 +1,5 @@
 # TC: O(H)
-# SC: O(1)
+# SC: O(H)
 # Definition for a binary tree node.
 # class TreeNode:
 #     def __init__(self, x):

From d37475c004a80069819dfdd953c1ef40595de60d Mon Sep 17 00:00:00 2001
From: Yuseok Jo <yuseok89@gmail.com>
Date: Sat, 19 Sep 2026 20:57:49 +0900
Subject: [PATCH 6/6] =?UTF-8?q?=EB=B3=B5=EC=9E=A1=EB=8F=84=20=EC=88=98?=
 =?UTF-8?q?=EC=A0=95?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 insert-interval/yuseok89.py               | 4 ++--
 kth-smallest-element-in-a-bst/yuseok89.py | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/insert-interval/yuseok89.py b/insert-interval/yuseok89.py
index 1a94271d4d..08c278fb89 100644
--- a/insert-interval/yuseok89.py
+++ b/insert-interval/yuseok89.py
@@ -1,5 +1,5 @@
-#TC: O(1)
-#SC: O(2)
+#TC: O(N)
+#SC: O(N)
 class Solution:
     def insert(self, intervals: list[list[int]], newInterval: list[int]) -> list[list[int]]:
 
diff --git a/kth-smallest-element-in-a-bst/yuseok89.py b/kth-smallest-element-in-a-bst/yuseok89.py
index 39ddefdce3..71efa31e6d 100644
--- a/kth-smallest-element-in-a-bst/yuseok89.py
+++ b/kth-smallest-element-in-a-bst/yuseok89.py
@@ -1,5 +1,5 @@
 # TC: O(N)
-# SC: O(1)
+# SC: O(H)
 # Definition for a binary tree node.
 # class TreeNode:
 #     def __init__(self, val=0, left=None, right=None):