<combinations> ( seq k -- combinations )

Vocabulary

math.combinatorics

Inputs

seq	a sequence
k	a non-negative integer

Outputs

combinations

a sequence

Word description

An efficient sequence containing the combinations of seq choosing k elements.

Definition

USING: kernel sequences ;

IN: math.combinatorics

: <combinations> ( seq k -- combinations )
    2dup [ length ] [ nCk ] bi* combinations boa ;