From 715e0e06f7e39dd2f8f0d354ef624c85d0b87bf6 Mon Sep 17 00:00:00 2001
From: KyungJin Jung <okyungjin@gmail.com>
Date: Sat, 12 Sep 2026 18:02:53 +0900
Subject: [PATCH 1/3] 435. Non-overlapping Intervals

---
 non-overlapping-intervals/okyungjin.py | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 non-overlapping-intervals/okyungjin.py

diff --git a/non-overlapping-intervals/okyungjin.py b/non-overlapping-intervals/okyungjin.py
new file mode 100644
index 0000000000..4925f9af0b
--- /dev/null
+++ b/non-overlapping-intervals/okyungjin.py
@@ -0,0 +1,22 @@
+"""
+https://leetcode.com/problems/non-overlapping-intervals/
+
+Time: O(N)
+Space: O(1)
+"""
+class Solution:
+    def eraseOverlapIntervals(self, intervals: List[List[int]]) -> int:
+        # 1. end 오름차순 intervals 정렬
+        intervals.sort(key=lambda x: x[1])
+
+        # remove count
+        count = 0        
+        last_end = float('-inf')
+
+        for start, end in intervals:
+            if start >= last_end: # 구간 안 겹침
+                last_end = end
+            else: # 구간 겹침
+                count += 1
+            
+        return count

From 61e469208e997687888b2551abf0abd2097886df Mon Sep 17 00:00:00 2001
From: KyungJin Jung <okyungjin@gmail.com>
Date: Sat, 12 Sep 2026 18:30:00 +0900
Subject: [PATCH 2/3] 100. Same Tree

---
 same-tree/okyungjin.py | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 same-tree/okyungjin.py

diff --git a/same-tree/okyungjin.py b/same-tree/okyungjin.py
new file mode 100644
index 0000000000..bb59f630a3
--- /dev/null
+++ b/same-tree/okyungjin.py
@@ -0,0 +1,35 @@
+"""
+https://leetcode.com/problems/same-tree/description/
+
+N: min(p노드수, q노드수)
+Time: O(N)
+Space: O(N)
+"""
+
+# 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 isSameTree(self, p: Optional[TreeNode], q: Optional[TreeNode]) -> bool:
+        queue = deque([(p, q)])
+
+        while queue:
+            node_p, node_q = queue.popleft()
+
+            if not node_p and not node_q:
+                continue
+
+            elif node_p and node_q:
+                if node_p.val == node_q.val: 
+                    queue.append((node_p.left, node_q.left))
+                    queue.append((node_p.right, node_q.right))
+                else:
+                    return False
+            
+            else:
+                return False
+
+        return True

From fc04e6aebbe097c769a3a39c77a946a1a5eec382 Mon Sep 17 00:00:00 2001
From: KyungJin Jung <okyungjin@gmail.com>
Date: Sat, 12 Sep 2026 18:32:11 +0900
Subject: [PATCH 3/3] =?UTF-8?q?435.=20Non-overlapping=20Intervals=20(?=
 =?UTF-8?q?=EC=8B=9C=EA=B0=84=20=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

---
 non-overlapping-intervals/okyungjin.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/non-overlapping-intervals/okyungjin.py b/non-overlapping-intervals/okyungjin.py
index 4925f9af0b..5fc005fb25 100644
--- a/non-overlapping-intervals/okyungjin.py
+++ b/non-overlapping-intervals/okyungjin.py
@@ -1,12 +1,12 @@
 """
 https://leetcode.com/problems/non-overlapping-intervals/
 
-Time: O(N)
+Time: O(N log N), intervals 정렬
 Space: O(1)
 """
 class Solution:
     def eraseOverlapIntervals(self, intervals: List[List[int]]) -> int:
-        # 1. end 오름차순 intervals 정렬
+        # end 오름차순 intervals 정렬
         intervals.sort(key=lambda x: x[1])
 
         # remove count