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  1. USING: sequences kernel arrays strings math.parser math
  2.     math.ranges io splitting ;
  3. IN: kaprekar
  4.  
  5. : cleave-at ( str n -- seq ) cut-slice [ >string ] bi@ 2array ;
  6.  
  7. : all-cleaves ( str -- seq ) [ length 1 - ] [ ] bi [ ] curry
  8.     replicate [ 1 ] [ length ] bi [a,b] [ cleave-at ] 2map ;
  9.  
  10. : filter-zeroes ( seq -- seq ) [ [ string>number ] map ] map
  11.     [ 0 swap member? not ] filter ;
  12.  
  13. : kaprekar? ( n -- ? ) dup sq number>string
  14.     all-cleaves filter-zeroes [ sum ] map member? ;
  15.  
  16. : main ( -- ) lines [ " " split [ string>number ] map [ first ]
  17.     [ second ] bi [a,b] [ kaprekar? ] filter >array
  18.     [ bl ] [ number>string write ] interleave nl ] each ;
  19.  
  20. MAIN: main
Success #stdin #stdout 0.21s 158016KB
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stdin 
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Standard output is empty
https://ideone.com/y8VmPq
language:
Factor (factor-0.93)
created:
8 years ago
visibility:
public

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