Solve a problem to calculate the maximum stock price difference.
Given an array of daily stock prices, return the largest difference prices[j] - prices[i] where i < j. You may buy once and sell once. Return 0 if no positive difference is possible.
Function: def max_stock_price_difference(prices): Input is a non-empty list of integers, and output is an integer.
def max_stock_price_difference(prices):