add-binary-exponentiation (#790)

maths/BinaryExponentiation.py

@@ -0,0 +1,25 @@
+#Author : Junth Basnet
+#Time Complexity : O(logn)
+
+def binary_exponentiation(a, n):
+    
+    if (n == 0):
+        return 1
+    
+    elif (n % 2 == 1):
+        return binary_exponentiation(a, n - 1) * a
+    
+    else:
+        b = binary_exponentiation(a, n / 2)
+        return b * b
+
+    
+try:
+    base = int(input('Enter Base : '))
+    power = int(input("Enter Power : "))
+except ValueError:
+    print ("Invalid literal for integer")
+
+result = binary_exponentiation(base, power)
+print("{}^({}) : {}".format(base, power, result))
+