Price garden centre till baskets with mixed 3-for-2 groups, 2-for-a-price bags, a spend coupon and loyalty points

# Price a garden centre's till baskets with multibuy offers Inputs: `baskets.csv` (one row per product line in each basket: basket id, sku, quantity), `products.csv` (shelf price and offer group of each sku) and `offers.json` (what each offer group means, and the coupon). Every amount is in pounds. Pricing rules, per basket: - 3 for 2: put every unit from the same 3-for-2 offer group in the basket in one list (different skus in a group mix), sorted by price from highest to lowest; every third unit in that list is free. - 2 for a fixed price: put every unit of the group in one list sorted by price from highest to lowest and pair them off from the top; each pair costs the group's pair price, and a leftover unit pays its own price. - Products with no offer group pay their shelf price. - Coupon: 5.00 off when the basket total after offers is 40.00 or more. - Loyalty points: 1 point per whole pound of the amount paid. Write `out/baskets.json`: `{"three_for_two_savings": {"<basket_id>": <saving from 3-for-2 groups>, ...}, "pair_savings": {"<basket_id>": <saving from 2-for-a-price groups>, ...}, "offer_savings": {"<basket_id>": <shelf total minus total after offers>, ...}, "paid": {"<basket_id>": <amount paid after offers and coupon>, ...}, "points": {"<basket_id>": <integer>, ...}, "total_paid": <sum of paid>}` with every basket. ## How this run works - Work on your own: nobody will answer questions in this task, and writing to `ask/` counts against the run. - Write only under `out/`. Create `out/` if it is missing. Inputs are synthetic; don't fetch anything from the network. - Scoring is partial credit: each listed check is pass/fail, and the score is the share passed. Numbers are compared to within 0.005 unless the task says otherwise.