From bd7583dc611da41967e1998a78cb9409eab7138f Mon Sep 17 00:00:00 2001
From: jongwanra <najongsi@gmail.com>
Date: Tue, 26 Aug 2025 07:14:26 +0900
Subject: [PATCH 1/2] add valid-parentheses solution

---
 valid-parentheses/jongwanra.py | 46 ++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 valid-parentheses/jongwanra.py

diff --git a/valid-parentheses/jongwanra.py b/valid-parentheses/jongwanra.py
new file mode 100644
index 000000000..c3489c152
--- /dev/null
+++ b/valid-parentheses/jongwanra.py
@@ -0,0 +1,46 @@
+"""
+[Problem]
+https://leetcode.com/problems/valid-parentheses/
+
+[Brainstorming]
+1. 여는 괄호가 나올 경우에 Stack에 Push한다.
+2. 닫는 괄호가 나왔을 경우에 Stack 가장 위에 여는 괄호와 일치 여부를 확인한다.
+
+이렇게 했을 때, 시간 복잡도는 O(N)으로 예상한다. (여기서 N은  s.length)
+
+[Complexity]
+Time: O(N), N = s.length
+Space: O(N), N = stack.length
+"""
+from os import popen
+
+
+class Solution:
+    def isValid(self, s: str) -> bool:
+        bracket_dict = {'(':')', '{':'}', '[':']'}
+        stack = []
+        for bracket in s:
+            # 여는 괄호인 경우 Stack 추가
+            if bracket in bracket_dict:
+                stack.append(bracket)
+                continue
+
+            # 닫는 괄호인 경우
+            if not stack or bracket_dict[stack.pop()] != bracket:
+                return False
+
+        return not stack
+
+sol = Solution()
+
+# Normal Case
+print(sol.isValid("()") == True)
+print(sol.isValid("()[]{}") == True)
+print(sol.isValid("(]") == False)
+print(sol.isValid("([])") == True)
+print(sol.isValid("([)]") == False)
+
+# Edge Case
+print(sol.isValid("(") == False)
+print(sol.isValid("]") == False)
+

From b45e7f69a0098d58c15fac949fd22283aade0505 Mon Sep 17 00:00:00 2001
From: jongwanra <najongsi@gmail.com>
Date: Mon, 1 Sep 2025 07:14:25 +0900
Subject: [PATCH 2/2]  refactor: apply reviewer suggestions to
 valid-parentheses solution

---
 valid-parentheses/jongwanra.py | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/valid-parentheses/jongwanra.py b/valid-parentheses/jongwanra.py
index c3489c152..1ae426fcc 100644
--- a/valid-parentheses/jongwanra.py
+++ b/valid-parentheses/jongwanra.py
@@ -12,8 +12,6 @@
 Time: O(N), N = s.length
 Space: O(N), N = stack.length
 """
-from os import popen
-
 
 class Solution:
     def isValid(self, s: str) -> bool:
@@ -23,11 +21,12 @@ def isValid(self, s: str) -> bool:
             # 여는 괄호인 경우 Stack 추가
             if bracket in bracket_dict:
                 stack.append(bracket)
-                continue
-
             # 닫는 괄호인 경우
-            if not stack or bracket_dict[stack.pop()] != bracket:
-                return False
+            else:
+                if not stack:
+                    return False
+                if bracket_dict[stack.pop()] != bracket:
+                    return False
 
         return not stack
 
@@ -44,3 +43,4 @@ def isValid(self, s: str) -> bool:
 print(sol.isValid("(") == False)
 print(sol.isValid("]") == False)
 
+