PROBLEM LINK:
Author:rahul_ojha_07
DIFFICULTY:
CAKEWALK
PREREQUISITES:
Binary numbers,Bit Manipulation
PROBLEM:
Given the total number of biscuits Bruno ate, find the number of days he was active?
QUICK EXPLANATION:
Calculate the Binar form of the given Number and count the number of 1's
EXPLANATION:
Since for each day the biscuits doubles up as the previous day with 1 biscuits on the first day, starting from i=0, the number of biscuits Bruno supposed to have on ith day is 2i
. Only the days he was active he got biscuits. So adding the power of 2 on each day he was active, gives the total number of biscuits, i.e., N. Hence, number of 1 in the binary representation of N is the number of days he was active.
Author's solution can be found here.