Why does trying every buy/sell pair become slow?
Practice this question from Best Time to Buy and Sell Stock - Greedy Pattern Practice Quiz, with options and an explanation.
Question
Why does trying every buy/sell pair become slow?
Option A
It sorts the prices incorrectly
Option B — Correct answer
It checks too many buy/sell pairs
Option C
It cannot return zero
Option D
It uses a stack
Explanation
Each buy day may be paired with many later sell days, causing O(n^2) work.