PROBLEM LINKS:
Difficulty:
Easy
Pre-requirements:
Decimal-Octal conversion
Problem:
Find the frequence of digit 5 in the octal representation of the given decimal number N.
1<=N<=1018
Explanation:
The digits in the octal representation can be easily obtained by continously dividing by 8 and finding the remainder till N becomes Zero. Remainder in each iteration represents a digit in octal representation.
Use a count variable to count the number of times the remainder is 5
complexity: O(log(N))
Authors Solution:
can be found here