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HS08FOUR - Four colors |
Let there be given n points: P1, P2 ... Pn arranged in this order on a line. We would like to color them using four colors: white, black, red, and blue, in such a way that for every three consecutive points it is true that either:
- 1. the colors of these three points are pairwise distinct, or
- 2. the color of some point is white.
Input
An integer T, denoting the number of testcases (T < 100000). In each line you are given one positive integer (n < 1000000000). There are 5 input sets.
Output
Find the number of possible colorings of the n points. Since the answer can be very big, output only the answer modulo 1000000007.
Example
Input:
4
1
2
3
1000
Output:
4
16
43
283570349
Warning: large input/output data, be careful with certain languages
Warning: A naive algorithm will probably solve only the first input set.
Added by: | Robert Gerbicz |
Date: | 2009-04-05 |
Time limit: | 1s |
Source limit: | 4096B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ERL JS-RHINO |
Resource: | High School Programming League 2008/09 |
hide comments
2022-08-30 08:30:19
for debugging: 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 4 4 4 4 4 1 2 2 4 2 1 2 4 2 2 1 16 16 16 16 9 4 6 6 9 6 4 6 9 6 6 4 43 43 43 43 32 16 22 22 32 22 16 22 32 22 22 16 139 139 139 139 103 43 65 65 103 65 43 65 103 65 65 43 448 448 448 448 312 139 204 204 312 204 139 204 312 204 204 139 1384 1384 1384 1384 995 448 652 652 995 652 448 652 995 652 652 448 |
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2014-12-17 02:28:48 Francky
AC at first try and rank #1 with 0.17s. It won't be easy to take it. Many thanks for this problem, I would have make such a problem, I didn't see it before. Now, I'll try to do better, if I can. |
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2014-12-15 11:56:52 abdou_93
not easy to get accepted |
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2013-12-11 10:33:51 Zhouxing Shi
passed with 5*5 matrix!! |
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2010-11-16 02:10:45 ymGXX
Great problem! |
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2010-07-08 12:43:14 刘启鹏
nice problems :) |
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2009-08-13 18:28:34 .:: Pratik ::.
I have AC with 4*4 ( see 1e5 cases ) Good luck, try to avoid mod. Time limit is super strict (but that is common with this author who has super fast solutions) |
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2009-08-13 18:13:09 Oleg
Can I ask another hint? do you have 4*4 matrix or reduced it to 3*3 or less ? |
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2009-08-13 18:12:08 Oleg
Yes, this is what I tried. I precomputed all low (1024) combintations, mid(1024) and high (1024) - so have only 3 multiplication. still TL :( |
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2009-08-13 17:38:26 .:: Pratik ::.
Lot of optimizations are needed to get accepted. ( HINT : reduce matrix multiplications with some (many) precomputations ) |