Most profit

input-statement.txt

You will be given a list of stock prices for a given day and your goal is to return the 
maximum profit that could have been made by buying a stock at the given price and then selling the 
stock later on. For example if the input is: [45, 24, 35, 31, 40, 38, 11] then your program should 
return **16** because if you bought the stock at $24 and sold it at $40, a profit of $16 was made and 
this is the largest profit that could be made. If no profit could have been made, return -1.

If the given array is {100, 180, 260, 310, 40, 535, 695}, the maximum profit can earned by buying 
on day 0, selling on day 3 (+210). Again buy on day 4 and sell on day 6 (+650). If the given array of prices is 
sorted in decreasing order, then profit cannot be earned at all.

most-profit.py

from functools import reduce

def max_profit(values):
  def one_diff(subvalues):
    diff_list = [-subvalues[0] + e for e in subvalues[1::]]
    return  max(diff_list) if (len(diff_list) > 1) else 0

  return max([one_diff(values[i::]) for i in range(0, len(values))])

"""
In [1]: max_profit([7, 6, 4 ,3 ,1])
Out[79]: 0

In [2]: max_profit([7,1,5,3,6,4])
Out[80]: 5

In [3]: max_profit([100, 180, 260, 310, 40, 535, 695])
Out[3]: 655
"""