Update maximum-product-of-the-length-of-two-palindromic-subsequences.py

Author: kamyu104

Python/maximum-product-of-the-length-of-two-palindromic-subsequences.py

@@ -32,7 +32,7 @@ def palindromic_subsequence_length(s, mask):
             # submask enumeration:
             # => sum(nCr(n, k) * 2^k for k in xrange(n+1)) = (1 + 2)^n = 3^n
             # => Time: O(3^n), see https://cp-algorithms.com/algebra/all-submasks.html
-            submask = inverse_mask = (len(dp)-1) ^ mask
+            submask = inverse_mask = (len(dp)-1)^mask
             while submask:
                 result = max(result, dp[mask]*dp[submask])
                 submask = (submask-1)&inverse_mask