I think that and the concept of Catalan Numbers does the trick. we seem to need to ignore the number of ways climbing the grid without ever going above the line y = x and that smacks of Catalan numbers.
2 candidates contested for an election, A & B. A got a votes, while B got b. Given a>b, find probability that A was ahead of B - throughout the competition..... SHOULD IT NOT BE JUST 12??????????????
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UP 0 DOWN 0 1 11
11 Answers
no Soumik I don't think it should be 1/2
simply because it should depend on a and b.
like take the case wehn B got zero votes. the probability is 1!
I think the best way to solve it would be through a axb grid...
What do you guys think?
One thing that is most commendable about prophet sir is that he knows the names of every trick under the sun :D
I din know that this was somethign related to Catalan number or infact it existed even though i have used this trick several times !!
i am not very familiar with it, but it did remind of that concept. Lets see
http://en.wikipedia.org/wiki/Bertrand%27s_ballot_theorem
Read this one..
Even i read catalan numbers last month..
I thought that this could be pulled off by recursion but now it seems unlikely....
see the proof on the page.. and the solution
btw I wont be here for 2 days.. bye till then [1]
the no of votes that A has more than B=a-b
so the probability that A can lead the election =a-b/a+b.
i hope this is rong,due to the above discussion,i just want to know why i am rong.
I dont get the logic sankara.. I mean how is it obvious to you.. to me it is not at all obvious!