P2983 [USACO10FEB]购买巧克力Chocolate Buying

    • 1.1K通过
    • 3.9K提交
  • 题目提供者 FarmerJohn2
  • 评测方式 云端评测
  • 标签 动态规划,动规,dp 背包 贪心 USACO 2010 高性能
  • 难度 普及/提高-
  • 时空限制 1000ms / 128MB

题解

  • 提示:收藏到任务计划后,可在首页查看。
  • 体验新版界面

    最新讨论 显示

    推荐的相关题目 显示

    题目描述

    Bessie and the herd love chocolate so Farmer John is buying them some.

    The Bovine Chocolate Store features N (1 <= N <= 100,000) kinds of chocolate in essentially unlimited quantities. Each type i of chocolate has price P_i (1 <= P_i <= 10^18) per piece and there are C_i (1 <= C_i <= 10^18) cows that want that type of chocolate.

    Farmer John has a budget of B (1 <= B <= 10^18) that he can spend on chocolates for the cows. What is the maximum number of cows that he can satisfy? All cows only want one type of chocolate, and will be satisfied only by that type.

    Consider an example where FJ has 50 to spend on 5 different types of chocolate. A total of eleven cows have various chocolate preferences:

    Chocolate_Type Per_Chocolate_Cost Cows_preferring_this_type 1 5 3

    2 1 1

    3 10 4

    4 7 2

    5 60 1

    Obviously, FJ can't purchase chocolate type 5, since he doesn't have enough money. Even if it cost only 50, it's a counterproductive purchase since only one cow would be satisfied.

    Looking at the chocolates start at the less expensive ones, he can * purchase 1 chocolate of type #2 for 1 x 1 leaving 50- 1=49, then * purchase 3 chocolate of type #1 for 3 x 5 leaving 49-15=34, then * purchase 2 chocolate of type #4 for 2 x 7 leaving 34-14=20, then * purchase 2 chocolate of type #3 for 2 x 10 leaving 20-20= 0.

    He would thus satisfy 1 + 3 + 2 + 2 = 8 cows.

    贝西和其他奶牛们都喜欢巧克力,所以约翰准备买一些送给她们。奶牛巧克力专卖店里

    有N种巧克力,每种巧克力的数量都是无限多的。每头奶牛只喜欢一种巧克力,调查显示,

    有Ci头奶牛喜欢第i种巧克力,这种巧克力的售价是P。

    约翰手上有B元预算,怎样用这些钱让尽量多的奶牛高兴呢?

    输入输出格式

    输入格式:

    * Line 1: Two space separated integers: N and B

    * Lines 2..N+1: Line i contains two space separated integers defining chocolate type i: P_i and C_i

    输出格式:

    * Line 1: A single integer that is the maximum number of cows that Farmer John can satisfy

    输入输出样例

    输入样例#1: 复制
    5 50 
    5 3 
    1 1 
    10 4 
    7 2 
    60 1 
    
    输出样例#1: 复制
    8 
    
    提示
    标程仅供做题后或实在无思路时参考。
    请自觉、自律地使用该功能并请对自己的学习负责。
    如果发现恶意抄袭标程,将按照I类违反进行处理。