NGON - Many polygons
There is a regular n-gon. We mark some points on its sides: a1 points on the first side, a2 on the second ... an on the last. Marked points do not coincide with the vertices n-gon. The question is, how many different convex nondegenerate (n-1)-gons you can build, using marked points as vertices?
Input
The first line of input contains the number t - the number of tests. Next comes the description of t tests. Each test consists of two lines. The first line of the test contains an integer n - number of vertices of original n-gon. Second line of the test lists n integers a1, a2 ... an - number of points marked on each side.
Constraints
1 <= t <= 20
4 <= n <= 1000
1 <= ai <= 100
Output
For each test, print out the answer to the problem modulo 1000000007.
Example
Input: 3 4 2 2 2 2 5 2 2 2 2 2 5 10 20 30 40 50 Output: 56 210 16207125
hide comments
David:
2021-04-23 20:05:02
Solved in Java!. After this problem, solve https://www.spoj.com/problems/SWARM/ |
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xodiac:
2017-11-16 19:28:38
too strict time limit for java |
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narek:
2014-09-21 13:09:34
Any more test cases? |
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Naman Goyal:
2014-07-12 14:27:14
mistake in modulo operation costed me so many WA's. Finally AC in 0.78sec. Last edit: 2014-07-12 16:27:50 |
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farhad chowdhury:
2014-06-14 12:34:04
Getting TLE
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Divanshu:
2013-03-25 09:46:47
Optimisations required to AC. Too strict time limit! |
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Alex Anderson:
2012-09-28 22:08:17
=|, Java is too slow, cause I am pretty confident in my last submission.
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Allada Revanth Kumar:
2012-02-04 13:36:55
could not understand, why i am getting wrong ans... all the test cases are working, fine please help me |
Added by: | Spooky |
Date: | 2010-03-12 |
Time limit: | 1s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: NODEJS OBJC PERL6 SQLITE VB.NET |
Resource: | Advancement Spring 2010, http://sevolymp.uuuq.com/ |