# Paste: n over k (choose)

Author: | randy |

Mode: | factor |

Date: | Wed, 1 Jul 2009 14:36:17 |

Plain Text |

USING: io kernel math math.order math.ranges sequences ;
IN: golf-choose
: nk-choose ( n-up k-down -- x )
2dup swap [ 0 ] dip between?
[
2dup - rot (a,b]
swap 1 max [1,b]
1 [ / * ] 2reduce
]
[ 2drop 0 ] if ;

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