MCIRGAME  Point Connection Game in a Circle
English  Vietnamese 
This is a small but ancient game. You are supposed to write down the numbers 1, 2, 3, . . . , 2n − 1, 2n consecutively in clockwise order on the ground to form a circle, and then, to draw some straight line segments to connect them into number pairs. Every number must be connected to exactly one another. And, no two segments are allowed to intersect. It’s still a simple game, isn’t it? But after you’ve written down the 2n numbers, can you tell me in how many diﬀerent ways can you connect the numbers into pairs? Life is harder, right!
Input
Each line of the input ﬁle will be a single positive number n, except the last line, which is a number −1. You may assume that 1 ≤ n ≤ 150. Sample Input 2 1
Output
For each n, print in a single line the number of ways to connect the 2n numbers into pairs. Sample output 2Note : Big num!
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phoemur:
20181102 20:46:10
In C++ you'll need an integer with 512 bits to hold the result for the given range.


babur:
20180622 20:16:06
Done using Pyhton. Has anyone solved it using c++. If yes, please share your approach. 

karthik_vg:
20180204 05:35:43
catalan using java BigInts (y) 

kshubham02:
20170904 11:58:54
MOD should have been given :/ 

Anuva Agarwal:
20141020 21:31:05
python made it pretty easy :D 

nitesh kumar:
20140725 14:07:14
simple dp plot the points on st line the try to solve subproblems!! 

Anubhav Balodhi :
20140330 15:34:17
One of the most famous sequences in Mathematics... great one ;) 

Nitish sharma:
20131029 20:43:03
Getting runtime error..any reason??


@looser@:
20130808 19:09:20
nice one 

Codeblooded:
20130808 14:15:18
does the answer require BigInt??? 
Added by:  ~!(*(@*!@^& 
Date:  20090223 
Time limit:  0.170s0.654s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ERL JSRHINO NODEJS PERL6 VB.NET 
Resource:  Pre Shanghai 2004 