Varen siblings + partners gift exchange pairings for Christmas 2024

varen_christmas_2024.py

import random
import pandas as pd
from tabulate import tabulate

SIBLINGS = ["McKenzie", "Reagan", "Danni", "Alex", "Thomas", "Ben", "Shane", "Eric", "Chris"]
PARTNERS = ["Emilie", "Julia", "Courtney", "Kirstyn", "Stefanie", "Rilka"]

sibling_partner_mapping = {
    "Alex": "Emilie",
    "Thomas": "Julia",
    "Ben": "Courtney",
    "Shane": "Kirstyn",
    "Eric": "Stefanie",
    "Chris": "Rilka"
}

assert all(s in SIBLINGS for s in sibling_partner_mapping.keys()), "Partner-havers must be siblings"
assert all(p in PARTNERS for p in sibling_partner_mapping.values()), "Partners must be in the partners list"

def generate_advanced_pairings(siblings, partners, sibling_partner_mapping, gifts_per_sibling, sibling_to_sibling_gifts):
    """
    - Each sibling gives `gifts_per_sibling` gifts
    - Partners aren't assigned to give gifts
    - Each sibling receives `sibling_to_sibling_gifts` gifts from other siblings
    - Each partner receives the remaining gifts, distributed as evenly as possible
    - Siblings don't give gifts to themselves
    - Siblings don't give gifts to their own partner
    - Siblings don't receive gifts from a sibling they're also giving a gift to (non-reciprocal)
    """
    pairings = {s: [] for s in siblings}
    total_gifts = len(siblings) * gifts_per_sibling
    sibling_gifts = len(siblings) * sibling_to_sibling_gifts
    partner_gifts = total_gifts - sibling_gifts

    # shuffle partners to ensure randomness
    random.shuffle(partners)

    partner_gift_counts = {p: partner_gifts // len(partners) for p in partners}
    extra_gifts = partner_gifts % len(partners)
    for i in range(extra_gifts):
        partner_gift_counts[partners[i]] += 1
    print(f"{partner_gift_counts=}")

    # generate sibling to sibling gifts ensuring non-reciprocity
    for giver in siblings:
        available = set(siblings) - {giver, sibling_partner_mapping.get(giver, '')}
        loop_count = 0
        while len(pairings[giver]) < sibling_to_sibling_gifts:
            assert loop_count < 1000, f"Looped too many times on {giver=!r}! Perhaps not solvable?"
            recipient = random.choice(list(available))
            if giver not in pairings[recipient]:
                pairings[giver].append(recipient)
                available.remove(recipient)
            loop_count += 1

    # assign partners ensuring not to give to own partner
    for giver in siblings:
        potential_partners = [p for p in partners if p != sibling_partner_mapping.get(giver, '') and partner_gift_counts[p] > 0]
        while potential_partners and len(pairings[giver]) < gifts_per_sibling:
            selected_partner = random.choice(potential_partners)
            pairings[giver].append(selected_partner)
            partner_gift_counts[selected_partner] -= 1
            potential_partners = [p for p in partners if p != sibling_partner_mapping.get(giver, '') and partner_gift_counts[p] > 0]

    return pairings


def main():
    gifts_per_sibling = 4
    sibling_to_sibling_gifts = 3

    pairings = generate_advanced_pairings(SIBLINGS, PARTNERS, sibling_partner_mapping, gifts_per_sibling, sibling_to_sibling_gifts)

    pairings_df = pd.DataFrame.from_dict(pairings, orient='index')

    pairing_len=len(list(pairings.items())[0][1])
    print(f"{pairing_len=} ,{list(pairings.items())[0][1]=}")
    print(tabulate(pairings_df, headers=[f"Sib Gift {x}" if x <=sibling_to_sibling_gifts else f"Partner Gift {x}" for x in range(1,pairing_len+1)], tablefmt='psql'))

if __name__ == "__main__":
    main()