leetcode #779

Author: guipleite

k-th-symbol-in-grammar.py

@@ -3,9 +3,12 @@
 class Solution:
     def kthGrammar(self, N: int, K: int) -> int:
 
+        if N == 0 or N is None or K is None:
+            return 0
+
         def backtrack(N,K):
 
-            if N==1 and K == 1 :
+            if N<=1 and K <= 1 :
                 return 0    
 
             size = 2**(N-2)