Update valid-parenthesis-string.py

kamyu104 · web-flow · commit 854b39993e47 · 2017-09-17T16:02:27.000+08:00
diff --git a/Python/valid-parenthesis-string.py b/Python/valid-parenthesis-string.py
@@ -9,16 +9,8 @@ def checkValidString(self, s):
         """
         lower, upper = 0, 0  # keep lower bound and upper bound of '(' counts
         for c in s:
-            if c == '(':
-                lower += 1
-                upper += 1
-            elif c == ')':
-                if upper == 0:  # '(' count is not enough
-                    return False
-                lower = max(lower-1, 0);
-                upper -= 1
-            else:
-                lower = max(lower-1, 0);
-                upper += 1
+            lower += 1 if c == '(' else -1
+            upper -= 1 if c == ')' else -1
+            if upper < 0: break
+            lower = max(lower, 0)
         return lower == 0  # range of '(' count is valid
-  
