From b564fc563ce37aec3e11be32970347168c7b42bb Mon Sep 17 00:00:00 2001
From: sangge-rockpi <2251250136@qq.com>
Date: Sat, 20 Jan 2024 13:43:21 +0800
Subject: [PATCH] add leetcode 20

---
 leetcode/20.py | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 leetcode/20.py

diff --git a/leetcode/20.py b/leetcode/20.py
new file mode 100644
index 0000000..e4eb84d
--- /dev/null
+++ b/leetcode/20.py
@@ -0,0 +1,26 @@
+# give a string s containing just '(', ')' and else
+# determine if the input is valid
+
+
+class Solution:
+    def isValid(self, s: str) -> bool:
+        symbol_dict = {"(": ")", "{": "}", "[": "]"}
+        stack = []
+        for i in s:
+            try:
+                stack_top = stack.pop()
+            except IndexError:
+                continue
+
+            try:
+                if symbol_dict[stack_top] == i:
+                    continue
+            except KeyError:
+                return False
+
+            stack.append(i)
+
+        if stack:
+            return False
+
+        return True