The School Fair Report

The fair is over; the money box holds a messy sales log. The principal wants a top-3 leaderboard. 🎪

You get the sales log as item:coins events (an item can appear many times — total them; at least 3 different items, all totals different). Print the top three earners, one per line, as <item> <total>, best first.

Example:

Input: sales = ["cake:5", "ring:3", "cake:2", "soda:4", "ring:9", "soda:1"] Output:

ring 12
cake 7
soda 5

Totaling gives cake = 5+2 = 7, ring = 3+9 = 12, soda = 4+1 = 5 — sorted biggest first, ring leads.