Given an array of stock prices for a day, where prices[i] is the price of the stock at time i, write a function that returns the maximum amount of money one could make in a day if he buys and sells at most once.

[10,1] -> return 0

[7,2,1,5,10,3] -> return 9

[5,6,7,1,2]

def stockPrices(prices):
profit = 0
for i in range(len(prices)):
for j in range(i+1,len(prices)):
if prices[j] - prices[i] > profit
profit = prices[j] - prices[i]
return profit