Paste: happy?

Author: rand
Mode: factor
Date: Fri, 6 Aug 2010 09:47:08
Plain Text | 
USING: assocs kernel math math.parser namespaces sequences ;
IN: happy-number

SYMBOL: repeating-numbers 

: reset-hash ( -- )
    H{ } clone repeating-numbers set ;

: add-repeat-number ( n -- )
    t swap repeating-numbers get set-at ;

: repeater? ( n -- ? )
    repeating-numbers get key? ;

: next-happy ( x -- y )
    number>string string>digits [ sq ] map sum ; 
    
: do-happy ( number -- ? )
    dup 1 = [ drop t ] [ 
        dup repeater?
        [ drop f ] [
            [ add-repeat-number ]
            [ next-happy do-happy ] bi
        ] if 
    ] if ; inline recursive

: happy? ( number -- ? )
    reset-hash do-happy ;

Annotation: another version

Author: jon
Mode: factor
Date: Sat, 7 Aug 2010 11:05:04
Plain Text | 
USING: combinators kernel math math.parser sequences sets ;
IN: bugtest

: squares ( n -- i ) number>string [ CHAR: 0 - sq ] [ + ] map-reduce ;
: (happy?) ( n set -- ? )
    { 
        { [ over 1 = ] [ 2drop t ] }
        { [ 2dup in? ] [ 2drop f ] }
        [ [ adjoin ] [ [ squares ] [ (happy?) ] bi* ] 2bi ]
    } cond ;
: happy? ( n -- ? ) HS{ } clone (happy?) ;

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