# 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.
# Find and return the maximum profit you can achieve.
# Note the problem is confusing - given per day prices, you make no profit buying
# and selling on the same day!
def 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
def main():
# First test: Best profit is buying at 1 and selling at 6 => profit = 5
prices = [7, 1, 5, 3, 6, 4]
debug_assert(total_profit(prices) == 7, "Assertion failed")
# Second test: No profitable day to sell => profit = 0
prices = [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 = [1, 2, 3, 4, 5]
debug_assert(total_profit(prices) == 4, "Assertion failed")