Calculate x ^ y in O(log n)
algorithm, big-o, c
Solution
This is called Exponentiation by Squaring. As far as implementation goes, it is a matter of taste. Your recursive implementation is good, but non-recursive implementations (from the link above) may look a little cleaner to people who do not like recursion or erroneously believe that it is somehow "wasteful" or "slow".
Problem
Interview question: Calculate x ^ y in O(log n) There are different answers like "Use the Indian Power algorithm" or ``` double power(double x, int y) { if(y == 0) return 1; double d = power(x, y/2); if(y%2 == 0) return d*d; else return x*d*d; } ``` is it a correct answer? is there any better way of writing a code for this question?