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TETRAHRD - Sum of Tetranacci numbers |
The sequence of Tetranacci numbers is defined as follows:
an = an-1 + an-2 + an-3 + an-4 with a0 = a1 = a2 = 0 and a3 = 1.
Input
Input starts with a positive integer t ≤ 4000, then t lines follow. Each of the t lines contains two space separated integers m and n with 0 ≤ m ≤ n ≤ 109.
Output
Calculate am + am+1 + ... + an and print the result modulo 1000000007.
Example
Input: 2 1 2 1919 5393 Output: 0 66616
Note: If your solution times out, you may try the tutorial version first.
Added by: | numerix |
Date: | 2012-02-26 |
Time limit: | 1s |
Source limit: | 10000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ASM64 |
Resource: | own problem |
hide comments
2021-04-12 17:53:21
with the correct solution time limit is enough |
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2017-08-30 22:08:24
Needs a lot of optimisations :) ... ac after many tle's |
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2017-07-18 00:56:23
Very strict time limit. Had to remove unnecessary mod operations to AC. TLE otherwise. |
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2015-08-10 16:58:22 Sarthak Taneja
Getting tle any suggestions?? |
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2013-01-02 11:43:00 Francky
It was really very hard to get AC with my order_4 python3 solution, but now we can say it's possible ! Edit : Python2 is still possible too without psyco. Last edit: 2013-01-02 20:36:24 |