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Best Time to Buy and Sell Stock with Cooldown

Question​

Given a list of prices for a stock over a set number of days, what is the maximum profit that can be obtained by buying and selling the stock exactly once, with a cooldown period between the buy and sell transactions?

Example 1
Input: [1,2,3,0,2]
Output: 3 (Buy at 1, sell at 3, cooldown at 0, buy at 0, sell at 2)

Solution​

all//Best Time to Buy and Sell Stock with Cooldown.py


# Dynamic programming solution

def maxProfit(prices):

    # if prices array is empty, return 0
    if not prices:
        return 0

    # create an array to store the maximum profit,
    # starting with 0 at the beginning
    max_profit = [0] * len(prices)

    # calculate the maximum profit for each day
    for i in range(1, len(prices)):

        # if today's price is lower than yesterday's price
        if prices[i] < prices[i-1]:

            # max profit on day i is max profit from yesterday
            max_profit[i] = max_profit[i-1]

        # if today's price is higher than yesterday's price
        else:

            # max profit on day i is either max profit from yesterday or
            # maximum profit from two days ago plus today's price minus two days ago's price
            max_profit[i] = max(max_profit[i-1], max_profit[i-2] + prices[i] - prices[i-2])

    # return the maximum profit from the last day
    return max_profit[-1]