You are given an integer array prices where prices[i] is the price of a given stock on the ith day.

On each day, you may decide to buy and/or sell the stock. You can only hold at most one share of the stock at any time. However, you can buy it then immediately sell it on the same day.

Note the problem is confusing - given per day prices, you make no profit buying and selling on the same day!

Find and return the maximum profit you can achieve.

fn total_profit(prices: List[UInt]) -> UInt:
    var total_profit: UInt = 0  # Stores the maximum profit found so far

    # Loop until sell day reaches the end of the price list
    for day in range(1, len(prices)):
        if prices[day - 1] < prices[day]:
            # If selling is profitable, sell it & add up profit
            total_profit += prices[day] - prices[day - 1]
    return total_profit  # Return the highest profit found


fn main():
    # First test: Best profit is buying at 1 and selling at 6 => profit = 5
    prices = List[UInt](7, 1, 5, 3, 6, 4)
    debug_assert(total_profit(prices) == 7, "Assertion failed")

    # Second test: No profitable day to sell => profit = 0
    prices = List[UInt](7, 6, 4, 3, 1)
    debug_assert(total_profit(prices) == 0, "Assertion failed")
    # 3rd test: Best profit is buying at every day and selling next day
    prices = List[UInt](1, 2, 3, 4, 5)
    debug_assert(total_profit(prices) == 4, "Assertion failed")

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