APS - Amazing Prime Sequence
Bablu is very fond of Series and Sequences...
After studying Fibonacci Series in Class IX, he was impressed and he designed his own sequence as follows...
a = a = 0
For n > 1, a[n] = a[n - 1] + f(n), where f(n) is smallest prime factor of n.
He is also very fond of programming and thus made a small program to find a[n], but since he is in Class IX, he is not very good at programming. So, he asks you for help. Your task is to find a[n] for the above sequence....
Your code will be checked for multiple Test Cases.
First Line of Input contains T (<= 100), the number of Test Cases.
Next T lines contain a single number N. (1 < N < 10^7).
Single line containing a[n] i.e. nth number of the sequence for each test case.
Input: 3 2 3 4 Output: 2 5 7
Nice problem ..
Awesome optimisation problem.
And if you use 64 bit signed integers, remember to use "%lld" instead of "%d"......
My 50th On spoj
Last edit: 2016-12-31 17:08:52
AC in one go!!! XD XD
Answer for 10000000 is 3203714961609 which is greater than the limit of a 32 bit signed integer. You must use long long, cost me a WA.
when legends copy http://www.spoj.com/problems/APS2/
nD here 100th completed with such a nice ques !!! modified sieve + precomputation . :)