Maximum Profit
You can obtain profits from foreign exchange margin transactions. For example, if you buy 1000 dollar at a rate of 100 yen per dollar, and sell them at a rate of 108 yen per dollar, you can obtain (108 - 100) × 1000 = 8000 yen.
Write a program which reads values of a currency Rt at a certain time t (t=0,1,2,...n−1), and reports the maximum value of Rj−Ri where j>i.