Yes, attack marrtin. The first and last orders, add up to profit, two orders are all closed, for example, 1, 2, 3, 4, 5, 1 and 5 add up to profit, 1 and 5 close. 2, 3, 4 left. Then open 5, 2 and 5 plus profit off, leaving 3, 4。 3 and 4 plus profit closing. If there is no profit, the newly opened...