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BRPAR - Brackets Parade |
Count the number of different correct bracket sequences consisting of k1 pairs of brackets of the 1st type, k2 pairs of brackets of the 2nd type … km pairs of brackets of the m-th type. The bracket sequence is considered correct in the following cases:
- empty sequence is correct;
- if A is correct and B is correct then AB is correct;
- if A is correct then (iA)i is correct where (i and )i are opening and closing brackets of the same type.
Input
The first line of input is the number 0 < n ≤ 1000 of test cases. Each of the following n lines describe a test case. Each line starts with number 0 < m ≤ 100 the amount of different bracket types. Then m positive numbers k1, k2 … km follow each separated with a space. Number ki is the amount of pairs of brackets of i-th type. The total amount of pairs of brackets is not greater than 1000.
Output
For each test case output a line containing single integer – the answer to the problem modulo 1000000007.
Example
Input: 3 1 4 2 2 2 3 1 2 3 Output: 14 84 7920
Added by: | Spooky |
Date: | 2009-04-11 |
Time limit: | 1s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ERL JS-RHINO NODEJS PERL6 VB.NET |
Resource: | Open All-Ukrainian Collegiate Contest Semi-Final, 2009 |
hide comments
2016-06-21 13:06:55 Piyush Kumar
People complaining about the TL, it is not at all strict. You must find the right solution. |
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2015-12-24 21:13:34
can anyone explain how the cases are working? |
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2013-09-11 10:06:41 moustafa maher
Can you extend the time to 20 second ,,, to pass my code and return it back to 1 after that !!!!! |
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2011-11-03 22:14:15 abualy
how can it be done in java?? :s re: don't use BigInteger Last edit: 2011-11-04 12:42:45 |
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2011-08-24 15:36:34 Spooky
nope... this can be derived from the definition... |
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2011-08-19 23:58:51 Ivan Sto¹iæ
is <open1><open2><closed1><closed2> a correct sequence? |
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2011-05-18 18:52:29 Naveen Jaiswal
how will one bracket even exist? |
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2010-02-05 18:15:11 numerix
No. |
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2010-01-03 00:05:58 Bommisetty Indraneel
I guess time limit is too tight for python? |