Stock Profit with At Most Two Transactions

Problem

Given daily prices, return the maximum profit from at most two non-overlapping buy-then-sell transactions.

Track four state variables in a single pass: the best first buy, first sell, second buy and second sell. Return 0 when no profitable pair of transactions exists.

Hint

sell1 - p is the effective cost of the second buy after banking the first profit.

Test cases

case 1

in: [[3,3,5,0,0,3,1,4]]

expected: 6

case 2

in: [[1,2,3,4,5]]

expected: 4

case 3

in: [[7,6,4,3,1]]

expected: 0

case 4

in: [[]]

expected: 0

case 5

in: [[1]]

expected: 0

Starter codePython

def max_profit_at_most_two(prices):
    # Your code here
    pass

5 test cases · run your code against them in the editor