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FIBOSUM - Fibonacci Sum |
The Fibonacci sequence is defined by the following relation:
- F(0) = 0
- F(1) = 1
- F(N) = F(N - 1) + F(N - 2), N >= 2
Your task is very simple. Given two non-negative integers N and M, you have to calculate the sum (F(N) + F(N + 1) + ... + F(M)) mod 1000000007.
Input
The first line contains an integer T (the number of test cases). Then, T lines follow. Each test case consists of a single line with two non-negative integers N and M.
Output
For each test case you have to output a single line containing the answer for the task.
Example
Input: 3 0 3 3 5 10 19 Output: 4 10 10857
Constraints
- T <= 1000
- 0 <= N <= M <= 109
Added by: | David Gómez |
Date: | 2010-12-04 |
Time limit: | 1s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ASM64 |
Resource: | My Own |
hide comments
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2016-02-24 21:16:50
It is possible in C #Vmcode by using matrix exponantion and sum of fibonacci series!!!!AC in 0.01s |
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2016-02-24 13:12:19 minhthai
that negative modulo tho ( ͡° ͜ʖ ͡°) |
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2016-01-10 16:59:05
i am getting nzec error by pyth 2.7 please help me out it says"maximum recursion depth reached" |
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2015-12-08 15:59:13 Vmcode
how is it possible in c??? |
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2015-09-14 07:36:45 MishThi
4 Days !! And victory.. :D Learnt a lot through this question. |
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2015-09-06 16:11:18 Harsh Vardhan Ladha
it is not given that M>=N causing many to get negative and negative MOD problem. Tweak a little! |
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2015-08-26 14:17:46
i wrote the code for this and i am gettingb negative ans so how do i handle this part Last edit: 2015-08-26 14:18:37 |
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2015-08-23 23:11:22
@Babu, if you do sum(M) - sum(N - 1), the latter one can be bigger than the former due to the modulus application. To solve that, just sum 10^9 + 7 to the result while it is negative. |
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2015-07-26 21:37:47 Babu
where is the negative modulus coming . please answer |
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2015-07-18 20:39:57 Rahul Jain
@xxbloodysantaxx, Your comment was very helpful to me. Thanks. Guys, just try taking out a recurrence for S(n) rather than expressing the sum in fibonacci term.... Will make you feel better surely :√) Well, negative modulus costed me 3 WAs Last edit: 2015-07-18 23:00:59 |