Update binary_search.py (#657)

Author: ChillOrb

algorithms/search/binary_search.py

@@ -1,9 +1,13 @@
 #
 # Binary search works for a sorted array.
 # Note: The code logic is written for an array sorted in
-#       increasing order.
-# T(n): O(log n)
-#
+#  increasing order.
+#For Binary Search, T(N) = T(N/2) + O(1) // the recurrence relation
+#Apply Masters Theorem for computing Run time complexity of recurrence relations : T(N) = aT(N/b) + f(N)
+#Here, a = 1, b = 2 => log (a base b) = 1 
+# also, here f(N) = n^c log^k(n) //k = 0 & c = log (a base b) So, T(N) = O(N^c log^(k+1)N) = O(log(N))
+
+
 def binary_search(array, query):
     lo, hi = 0, len(array) - 1
     while lo <= hi: