ocaml: phase 5.1 powerset_target.ml baseline (subsets of {1..10} summing to 15 = 20)

Recursive powerset construction by doubling:

  let rec gen xs = match xs with
    | [] -> [[]]
    | h :: rest ->
      let sub = gen rest in
      sub @ List.map (fun s -> h :: s) sub

Enumerates all 2^10 = 1024 subsets, filters by sum:

  count = |{ S ⊆ {1..10} | Σ S = 15 }| = 20

Examples: {1,2,3,4,5}, {2,3,4,6}, {1,4,10}, {7,8}, {6,9}, ...

Tests recursive subset construction via List.map + closures,
pattern matching with h :: rest, List.fold_left (+) 0 sum reduce,
exhaustive O(2^n * n) traversal.

172 baseline programs total.

lib/ocaml/baseline/expected.json

@@ -132,6 +132,7 @@
   "poly_stack.ml": 5,
   "polygon_area.ml": 32,
   "pow_mod.ml": 738639,
+  "powerset_target.ml": 20,
   "prime_factors.ml": 17,
   "pythagorean.ml": 16,
   "queens.ml": 2,