Return the nth rational number.
This is the inverse to Problem 1471. Index of a Rational number
The first ten positive rational numbers under the enumeration using cantors diagonalization argument are 1/1, 2/1, 1/2, 3/1, 2/2, 1/3, 4/1, 3/2, 2/3, 1/4.
Find the index of a positive rational number enumerated in this manner, i.e. the 6th rational number is 1/3.
Solution Stats
Problem Comments
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2 Comments
Massimo Zanetti
on 7 Oct 2016
Is that possible to have a ranking of the solutions based on their performing time? I think that the could be a method that is fast even if more sized.
Massimo Zanetti
on 10 Oct 2016
Solution
<http://it.mathworks.com/matlabcentral/cody/problems/1472-nth-rational-number/solutions/1006333>
provides inexpensive method. There is only one 2nd order polynomial solution and one division.
Solution Comments
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1 Comment
ABDELRAHMAN
on 10 Feb 2016
i get the same solution but the test says false
for test 9, 11
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1 Comment
Richard
on 28 Sep 2015
I thought we had to discount all the equivalent fractions (like 2/2) so I wrote this horrible cheat. How embarrassing.
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