Top 3 Companies by Stock Averages | Dataford Interview Questions

A financial insights prototype connected to Shopify Admin receives one week of stock prices for multiple companies. Find the three companies with the highest average stock price over the seven-day period.

Return their zero-based row indices, ordered from highest average to lowest. If two companies have the same average, place the company with the smaller index first.

Formal Specification

Implement top_three_companies(prices), where prices is a non-empty 2D array of numbers. Each row represents one company, and each row contains exactly seven daily prices. Return a list containing up to three integer row indices. If fewer than three companies are provided, return all available indices.

You may compare seven-day totals instead of averages because every company has the same number of days.

Constraints

1 <= len(prices) <= 10^5
Each company has exactly 7 daily prices
0 <= prices[i][j] <= 10^9
Prices may be integers or floating-point numbers
Return at most three indices

Function Signature

def top_three_companies(prices):

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