Arithmetic/Rational: Difference between revisions

(→‎{{header|J}}: Use lang tags)
Line 681:
 
faster version (but the problem, as stated, is still tremendously inefficient):
<lang j> factors=: ([: ~. ] */ .&>@{@((^"1 2: #:@i.@^ #>:)&.>/)@q: ::]~&__
is_perfect_rational=: 2= +/@:%@,@factors</lang>
 
<lang j> I.is_perfect_rational@"0 i.2^19
6,951

edits