If there are 38 people in a line and every 4th on is killed, where would you
stand?
josephus =: dyad define NB. explicit form, assume executioner starts at
position 0
NB. use: SKIP josephus NUMBER_OF_PRISONERS
N =: y
K =: N | x
EXECUTIONER =: 0
PRISONERS =: i. N
kill =: ] #~ (~: ([: i. #))
while. 1 (< #) PRISONERS do.
EXECUTIONER =: (# PRISONERS) | <: K + EXECUTIONER
PRISONERS =: EXECUTIONER kill PRISONERS
end.
)
3 josephus 41
30
4 josephus 38
37
jolla=: dyad define
B=:_1}"1 ((>.y%x) ,x)$i.y
G=:(-.2|y)|.(-.(i.y) e. B)#i.y
while. y>$B do.
B=:B,_1{"1((>.($G)%x) ,x)$G
G=:(-.(i.y) e. B)#i.y
end.
_1}B
)
3 jolla 41
30
4 jolla 38
18
David Lambert's function chooses the 37th position. Mine chooses the e.
Where would you stand?
Linda
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of David Ward
Lambert
Sent: Thursday, April 18, 2013 11:20 PM
To: programming
Subject: [Jprogramming] rosettacode
Please modify these new entries as you please:
http://rosettacode.org/wiki/Josephus_problem#J
http://rosettacode.org/wiki/Continued_fraction/Arithmetic/Construct_from_rat
ional_number#J
The continued fraction solution has some oddities. Returning _ to signal
"finished" converts the output vector to floating point. That's why I
excluded the 314285714 100000000x example. The `y is 8' input to r2cf__CF
is arbitrary and I have to strip it with _ from the output vector.
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