FIBOFUN - Fun with Fibonacci Series

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Fibonacci series is a series in which every element is sum of previous 2 elements.

first 2elements are 0,1 and the series goes like 0,1,1,2,3,5,8,13 ........


What if you were given 2 random numbers as the starting of the series and u follow the same rule as the fibonacci rule.

for eg. if you were given 2 and 2 .. the series would become

2 2 4 6 10 16 26 .........


Now ur task is Simple ...

You will be given 2 numbers a & b .. the first and second term of the series..

you need to calculate the sum of first n numbers of the series so formed..

Since the numbers can be big you need to print the result mod some number 'M' provided in the input.


first line will have single number 't' - number of test cases.

each test case will have 4 numbers a,b,n & M

a- first number of the series

b- second number of the series

n- calculate the sum till n numbers

M- print the result mod M


single number for each case - sum of n terms mod M


2 2 10 21
1 3 10 21

 Output: 13

Explanation - for first case series is 2 2 4 6 10 16 26 42 68 110 .. Sum is 286.. o/p = 286%21 = 13
Number of test cases <=100.
0 <= a,b,m <= 10^8
1 <= n <= 10^8
actually n ranges from 1 to 10^8

hide comments
Shubham Jadhav: 2017-05-12 04:10:06

AC in one go :)

Ankur Singh: 2016-07-17 08:38:03

Don't forget to take the MOD, even for small cases of n like 1, 2.

Satyam Mishra: 2015-06-13 10:05:20

Nice problem..
learnt a lot.

__hk__: 2015-06-09 11:57:26

Finally AC..!!
Learnt a faster way of generating fibonacci numbers !!!

ALISHA: 2014-12-24 21:30:20

Never matters whether it's in tutorial or classical section. All that matters is the bliss of getting green band in first attempt.Rest is all greed my friend.:P

Last edit: 2014-12-24 21:31:14
success: 2014-12-10 08:26:05

plz check my code why wrong answer.?
plz reply

Last edit: 2014-12-10 10:52:41
Francky: 2014-01-24 18:33:28

I very well know Fibonacci variation's problems here at spoj, and I can confirm that this one don't give new materials. It is a tutorial problem for several reasons. I don't say it is an easy problem. Please trust EB members in their actions ; stop asking for classical.

Somesh Maurya™: 2014-01-24 17:01:23

C'mon this isn't a tutorial problem... Move it to classical please...

Somesh Maurya™: 2014-01-24 17:00:31

What if m=0??

Arika Saputro: 2013-05-09 13:47:29

why my code giving WA?
can you check my code?

done.. ;D in any testcase, my solution give negative answer.. thanks, nice problem ;D

Last edit: 2013-05-09 13:58:10

Added by:Devil D
Time limit:1s
Source limit:10000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ASM64