From 71aa2d0c845b3f6b938cfb6e9b705b1a01f16155 Mon Sep 17 00:00:00 2001
From: prograsshopper <tjalwled12@gmail.com>
Date: Sat, 20 Dec 2025 23:28:23 +0900
Subject: [PATCH] week 6: valid parentheses

---
 valid-parentheses/prograsshopper.py | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 valid-parentheses/prograsshopper.py

diff --git a/valid-parentheses/prograsshopper.py b/valid-parentheses/prograsshopper.py
new file mode 100644
index 000000000..79a5ce995
--- /dev/null
+++ b/valid-parentheses/prograsshopper.py
@@ -0,0 +1,23 @@
+class Solution:
+    def isValid(self, s: str) -> bool:
+        # time complexity: O(n)
+        # space complexity: O(n)
+        opens = ['(', '[', '{']
+        closes = [')', ']', '}']
+        required = []
+        pair = {
+            '(': ')',
+            '[': ']',
+            '{': '}'
+        }
+        answer = True
+        for elem in s:
+            if elem in opens:
+                required.append(pair[elem])
+            else:
+                if elem in required and required[-1] == elem:
+                    required.pop()
+                else:
+                    answer = False
+                    break
+        return True if (answer and len(required) == 0) else False