Hofstadter Figure-Figure sequences: Difference between revisions

</pre>

=={{header|RPL}}==

{{works with|Halcyon Calc|4.2.8}}

{| class="wikitable"

! RPL code

! Comment

|-

|

≪ { 1 3 } 'R' STO { 2 } 'S' STO

≫ ''''INITFF'''' STO

≪

S DUP SIZE GET

'''DO''' 1 + '''UNTIL''' R OVER POS NOT '''END'''

S OVER + 'S' STO

R DUP SIZE GET + R SWAP + 'R' STO

≫ ''''NXTFF'''' STO

≪

''''WHILE''' R SIZE OVER < '''REPEAT NXTFF END'''

R SWAP GET

≫ ''''FFR'''' STO

≪

'''WHILE''' S SIZE OVER < '''REPEAT NXTFF END'''

S SWAP GET

≫ ''''FFS'''' STO

≪ '''INITFF'''

40 '''FFR''' DROP R

960 '''FFS''' DROP S +

1 SF 1 1000 '''FOR''' j

'''IF''' DUP j POS NOT '''THEN''' 1 CF '''END NEXT''' DROP

1 FS? "Passed" "Failed" IFTE

≫ ''''TASK4'''' STO

|

'''INITFF''' ''( -- ) ''

Initialize R(1..2) and S(1)

'''NXTFF''' ''( -- ) ''

n = last stored item of S()

n += 1 until n not in R()

append n to S()

append (n + last item of R()) to R()

'''FFR''' ''( n -- R(n) ) ''

if R(n) not stored, develop R()

Get R(n)

'''FFS''' ''( n -- S(n) ) ''

if S(n) not stored, develop S()

Get S(n)

'''TASK4''' ''( -- "Result" ) ''

Get R(40) and put R(1..40) in stack

Get S(960), append S(1..960) to R(1..40)

set flag ; for j=1 to 1000

if j not in the merged list then clear flag

Flag is still set iff all 1..1000 were in list once

|}

{{in}}

<pre>

10 FFR DROP R

TASK4

</pre>

{{out}}

<pre>

2: { 1 3 7 12 18 26 35 45 56 69 }

1: "Passed"