Hihocoder #1095 : HIHO Drinking Game （微软笔试题）

题目1 : HIHO Drinking Game

时间限制:10000ms

单点时限:1000ms

内存限制:256MB

描述

Little Hi and Little Ho are playing a drinking game called HIHO. The game comprises N rounds. Each round, Little Hi pours T milliliter of water into Little Ho's cup then Little Ho rolls a K-faces dice to get a random number d among 1 to K. If the remaining water in Little Ho's cup is less than or equal to d milliliter Little Hi gets one score and Little Ho drinks up the remaining water, otherwise Little Ho gets one score and Little Ho drinks exactly d milliliter of water from his cup. After N rounds who has the most scores wins.

Here comes the problem. If Little Ho can predict the number d of N rounds in the game what is the minimum value of T that makes Little Ho the winner? You may assume that no matter how much water is added, Little Ho's cup would never be full.

输入

The first line contains N(1 <= N <= 100000, N is odd) and K(1 <= K <= 100000).
The second line contains N numbers, Little Ho's predicted number d of N rounds.

输出

Output the minimum value of T that makes Little Ho the winner.

样例输入

5 63 6 6 2 1

样例输出

4

题意分析

小Hi和小Ho正在玩这样一个游戏，在每局游戏的开始，小Hi手持一瓶可以认为是无穷无尽的饮料，而小Ho手中有一个空杯子。

一局游戏分为N轮，在每轮行动中，小Hi先向小Ho手中的杯子倒入T个单位的饮料（倒入的数量在一局游戏开始之前约定好且在整局游戏中固定），然后小Ho掷出一个均匀的K面骰子得到一个1..K之间的数d，如果杯中饮料的单位数小于等于d，则小Hi记一分，且小Ho将杯中剩余饮料一饮而尽，否则小Ho记一分，小Ho喝掉杯中d个单位的饮料。在N轮结束后，分高者获胜。

那么问题来了，如果小Ho能够预测这局中每轮自己所掷出的点数，那么最小的能使得小Ho获胜的T（每轮小Hi倒入小Ho杯子的饮料的单位数）是多少？

杯子的饮料的单位数和你选着的T有关。

应为T越大Ho的分数就越大，所以可以用二分

中间题意没看懂，一直是WA。