FIBTWIST - Fibonacci With a Twist
Fibonacci numbers are given by
- f(n) = f(n-1) + f(n-2)
with f(0) = 0 and f(1) = 1.
first number of series ------ 0 1 1 2 3 5 8 13
Now let's have a new series called "Fibonacci Twist" which is given by
- ft(n) = ft(n-1) + ft(n-2) + (n-1)
with ft(0) = 0 and ft(1) = 1.
with first few number in the series ----- 0 1 2 5 10 19 34 59
Now your task is to find ft(n).
Since the number can be big you have to find the result mod M.
Input
first line having single number 't' -- number of test cases.
Next t lines have 2 number each 'n' and 'M'
Output
Single number given the n-th term mod M
Example
Input: 3 5 20 10 77 15 111 Output: 19 45 69
Constraints
- 10 <= t <= 100
- 0 <= n <= 10^9
- 100 <= M <= 10^9
Explanation
- ft(5) is 19. 19 % 20 = 19
- ft(10) is 276. 276 % 77 = 45
- ft(15) is 3177. 3177 % 111 = 69
hide comments
smso:
2023-06-06 17:40:54
If you solve by using formula, beware of overflow when n is big and M is small, e.g.
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adist98:
2019-06-19 00:09:23
Can anyone please explain this negative modulus case? I can't seem to wrap my head around this and somehow i see this everywhere. |
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milw0rm_007:
2018-06-19 10:25:17
@Devil D What is the problem with my solution?(Sub. ID 21860369) |
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sandeep_4141:
2017-06-23 11:51:02
same as FIBOSUM !! |
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divya_28:
2017-01-29 15:25:46
Do FIBOSUM before this. |
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MishThi:
2015-09-14 19:56:12
Solved FIBOSUM and then did some extra paperwork.. And Bazinga!
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Mayank Garg:
2015-08-19 16:35:50
No need of matrix exponentiation , if u r ready to do some calculations ..!! A simple formula ;) AC in 0.0s :p |
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Saksham :
2015-08-10 23:26:15
take care of -ve modulus
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anshal dwivedi:
2015-08-10 14:17:37
Ac in one go! by using 4X4 matrix... |
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:.Mohib.::
2015-06-24 11:15:18
2nd century on spoj with great que....learned a lot.... :) |
Added by: | Devil D |
Date: | 2012-04-19 |
Time limit: | 0.100s-1s |
Source limit: | 20000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ASM64 |
Resource: | Own |