solved leetcode 20, valid parentheses.python3 -u /Users/iamserda/repo…

…s/SWENG/neetcodeio/algostructybeginners/Lv1-Arrays/valid_parentheses.py

-@iamserda

neetcodeio/algostructybeginners/Lv1-Arrays/valid_parentheses.py

@@ -0,0 +1,26 @@
+def isValid(string: str) -> bool:
+    openers = set(list("{[("))
+    matching_set = {"{}", "[]", "()"}
+    stack = []
+
+    for char in string:
+        if char in openers:
+            stack.append(char)
+            continue
+        if not stack:
+            return False
+        if stack[-1] + char in matching_set:
+            stack.pop()
+            continue
+        return False
+
+    if len(stack) == 0:
+        return True
+    return False
+
+
+assert isValid("[") == False
+assert isValid("()") == True
+assert isValid("()[]{}") == True
+assert isValid("(]") == False
+assert isValid("([])") == True