Added two optimized pythonic functions and removed unnecessary semicolons.

strings/add_binary.py

@@ -24,3 +24,10 @@ def add_binary(a, b):
         # c //= 2 for python3
         c /= 2
     return s
+
+
+def add_binary_pythonic(a, b):
+    decimal_a = int('0b' + a, 2)
+    decimal_b = int('0b' + b, 2)
+    s = bin(decimal_a + decimal_b)[2:]
+    return s

strings/int_to_roman.py

@@ -9,11 +9,11 @@ def int_to_roman(num):
     :type num: int
     :rtype: str
     """
-    M = ["", "M", "MM", "MMM"];
-    C = ["", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"];
-    X = ["", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"];
-    I = ["", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"];
-    return M[num // 1000] + C[(num % 1000) // 100] + X[(num % 100) // 10] + I[num % 10];
+    M = ["", "M", "MM", "MMM"]
+    C = ["", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"]
+    X = ["", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"]
+    I = ["", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"]
+    return M[num // 1000] + C[(num % 1000) // 100] + X[(num % 100) // 10] + I[num % 10]
 
 
 print(int_to_roman(644))

strings/is_palindrome.py

@@ -34,3 +34,15 @@ def is_palindrome(s):
 
 # Time Complexity : O(len(s))
 # Space Complexity : O(1)
+
+
+def is_palindrome_pythonic(s):
+    """
+    :type s: str
+    :rtype: bool
+    """
+    alphanumerics = [c.lower() for c in s if c.isalnum()]
+    return alphanumerics == alphanumerics[::-1]
+
+# Time Complexity : O(len(s))
+# Space Complexity : O(len(s))