#103
Generating k-combinations
| Difficulty: | Medium |
| Topics: | seqs combinatorics |
Given a sequence S consisting of n elements
generate all k-combinations of S,
i.e. generate all possible sets consisting
of k distinct elements taken from S.
The number of k-combinations for a sequence
is equal to the binomial coefficient.
 | (= (__ 1 #{4 5 6}) #{#{4} #{5} #{6}}) |
| (= (__ 10 #{4 5 6}) #{}) |
| (= (__ 2 #{0 1 2}) #{#{0 1} #{0 2} #{1 2}}) |
| (= (__ 3 #{0 1 2 3 4}) #{#{0 1 2} #{0 1 3} #{0 1 4} #{0 2 3} #{0 2 4}
#{0 3 4} #{1 2 3} #{1 2 4} #{1 3 4} #{2 3 4}}) |
| (= (__ 4 #{[1 2 3] :a "abc" "efg"}) #{#{[1 2 3] :a "abc" "efg"}}) |
| (= (__ 2 #{[1 2 3] :a "abc" "efg"}) #{#{[1 2 3] :a} #{[1 2 3] "abc"} #{[1 2 3] "efg"}
#{:a "abc"} #{:a "efg"} #{"abc" "efg"}})) |