From c6d199d8cf06ed2378e10149aca709bd0bc73181 Mon Sep 17 00:00:00 2001
From: sejineer <jinpark99@nave.com>
Date: Fri, 23 May 2025 00:59:47 +0900
Subject: [PATCH 1/3] reverse-bits solution

---
 reverse-bits/sejineer.py | 12 ++++++++++++
 1 file changed, 12 insertions(+)
 create mode 100644 reverse-bits/sejineer.py

diff --git a/reverse-bits/sejineer.py b/reverse-bits/sejineer.py
new file mode 100644
index 000000000..ee97cdab2
--- /dev/null
+++ b/reverse-bits/sejineer.py
@@ -0,0 +1,12 @@
+"""
+시간 복잡도: O(1)
+공간 복잡도: O(1)
+"""
+class Solution:
+    def reverseBits(self, n: int) -> int:
+        result = 0
+        for _ in range(32):
+            result <<= 1
+            result |= n & 1
+            n >>= 1
+        return result

From 1743351aa38b939ebf34807c37e2e26248995f60 Mon Sep 17 00:00:00 2001
From: sejineer <jinpark99@nave.com>
Date: Sat, 24 May 2025 10:00:42 +0900
Subject: [PATCH 2/3] clone-graph solution

---
 clone-graph/sejineer.py | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 clone-graph/sejineer.py

diff --git a/clone-graph/sejineer.py b/clone-graph/sejineer.py
new file mode 100644
index 000000000..5dfbf9b28
--- /dev/null
+++ b/clone-graph/sejineer.py
@@ -0,0 +1,23 @@
+"""
+시간 복잡도: O(V + E) V: 노드 개수, E: 간선 개수
+공간 복잡도: O(V)
+"""
+from collections import deque
+from typing import Optional
+class Solution:
+    def cloneGraph(self, node: Optional['Node']) -> Optional['Node']:
+        if not node:
+            return
+        
+        clone = Node(node.val)
+        vis = {node: clone}
+        queue = deque([node])
+
+        while queue:
+            cur = queue.popleft()
+            for nxt in cur.neighbors:
+                if nxt not in vis:
+                    vis[nxt] = Node(nxt.val)
+                    queue.append(nxt)
+                vis[cur].neighbors.append(vis[nxt])
+        return clone

From ca4fdb75a7475964a9f1d67df454212aa1715ab8 Mon Sep 17 00:00:00 2001
From: sejineer <jinpark99@nave.com>
Date: Sat, 24 May 2025 10:35:47 +0900
Subject: [PATCH 3/3] palindromic-substrings solution

---
 palindromic-substrings/sejineer.py | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 palindromic-substrings/sejineer.py

diff --git a/palindromic-substrings/sejineer.py b/palindromic-substrings/sejineer.py
new file mode 100644
index 000000000..2d3104665
--- /dev/null
+++ b/palindromic-substrings/sejineer.py
@@ -0,0 +1,19 @@
+"""
+시간 복잡도: O(N^2)
+공간 복잡도: O(1)
+"""
+class Solution:
+    def countSubstrings(self, s: str) -> int:
+        result = 0
+        def count_palindrome(left: int, right: int):
+            count = 0
+            while left >= 0 and right < len(s) and s[left] == s[right]:
+                count += 1
+                left -= 1
+                right += 1
+            return count
+        
+        for i in range(len(s)):
+            result += count_palindrome(i, i)
+            result += count_palindrome(i, i + 1)
+        return result