by sum i mean the total distance already covrered
Consider a n*n chessboard. A person moves along the lines of the chessboard such that the sum in the y axis is greater than or equal to the sum in the x axis. Find the number of ways of going from one corner to the other corner.
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7 Answers
Sigma
·2012-04-27 01:33:00
@Shaswata: ur ans wud hav been correct if the q wud hav been: In how many shortest possible ways can 1 reach the diagonal opp sides of the chessboard??
Shubhodip
·2012-05-17 04:17:32
This is Catalan numbers.
The answer is C_{n-1}
Just look at the permutation matrix and you are done. (Basically a bijection)
I don't have time to explain sorry
sougata nag
·2012-06-03 00:59:57
let the no be g.
then 2g=Σ1→n2rCr+Σ1≤i,j≤ni+jCi
- Shubhodip what Upvote·0· Reply ·2012-06-06 09:41:33