20

Author: Jeldo

valid-parentheses/jeldo.py

@@ -0,0 +1,17 @@
+class Solution:
+    # O(n), n = len(s)
+    def isValid(self, s: str) -> bool:
+        parentheses = {
+            "(": ")",
+            "]": "]",
+            "{": "}",
+        }
+        stack = []
+        for ch in s:
+            if ch in parentheses.keys():
+                stack.append(ch)
+            elif stack and ch == parentheses[stack[-1]]:
+                stack.pop()
+            else:
+                return False
+        return len(stack) == 0