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  • P3243没有找零
    限制 : 时间限制 : 10000 MS   空间限制 : 65536 KB
    问题描述

    约翰到商场购物,他的钱包里有K(1 <= K <= 16)个硬币,面值的范围是1..100,000,000。
    约翰想按顺序买 N个物品(1 <= N <= 100,000),第i个物品需要花费c(i)块钱,(1 <= c(i) <= 10,000)。
    在依次进行的购买N个物品的过程中,约翰可以随时停下来付款,每次付款只用一个硬币,支付购买的内容是从上一次支付后开始到现在的这些所有物品(前提是该硬币足以支付这些物品的费用)。不幸的是,商场的收银机坏了,如果约翰支付的硬币面值大于所需的费用,他不会得到任何找零。
    请计算出在购买完N个物品后,约翰最多剩下多少钱。如果无法完成购买,输出-1

    原题目:
    Farmer John is at the market to purchase supplies for his farm. He has in
    his pocket K coins (1 <= K <= 16), each with value in the range
    1..100,000,000. FJ would like to make a sequence of N purchases
    (1 <= N <= 100,000), where the ith purchase costs c(i) units of money
    (1 <= c(i) <= 10,000). As he makes this sequence of purchases, he can
    periodically stop and pay, with a single coin, for all the purchases made
    since his last payment (of course, the single coin he uses must be large
    enough to pay for all of these). Unfortunately, the vendors at the market
    are completely out of change, so whenever FJ uses a coin that is larger
    than the amount of money he owes, he sadly receives no changes in return!

    Please compute the maximum amount of money FJ can end up with after making
    his N purchases in sequence. Output -1 if it is impossible for FJ to make
    all of his purchases.

    输入格式

    第一行,两个整数K和N
    接下来K行,每行一个整数,表示一个硬币的面值
    接下来N行,每行一个整数,一次给出了每个商品的价格

    输出格式

    一个整数,表示所求的结果

    样例输入

    3 6
    12
    15
    10
    6
    3
    3
    2
    3
    7

    样例输出

    12

    提示

    样例说明:
    约翰用10元面值的硬币购买了前两个物品,用15元面值的硬币购买了剩下的所有物品。