> POJ3627
> Bookshelf
> 书架
> 描述：
> Farmer John recently bought a bookshelf for cow library, but the shelf is getting filled up quite quickly, and now the only available space is at the top.
> 小A最近为图书馆买了一个书架，但书架几乎被填满了，只剩下顶部可以放了。
> Each of the N cows (1 ≤ N ≤ 20,000) has some height of Hi (1 ≤ Hi ≤ 10,000) and a total height summed across all N cows of S. The bookshelf has a height of B (1 ≤ B ≤ S < 2,000,000,007).
> 每个人（1<=N<=2e+4）都有身高（1<=Hi<=1e+4），并且身高总和为S，书架高度B。
> （1<=B<=S<2,000,000,007）
> To reach the top of the bookshelf taller than the tallest cow, one or more of the cows can stand on top of each other in a stack, so that their total height is the sum of each of their individual heights. This total height must be no less than the height of the bookshelf. Since more cows than necessary in the stack can be dangerous, your job is to find the set of cows that produces a stack of the smallest number of cows possible such that the stack can reach the bookshelf.
> 书架比最高的人还高，为了能碰到书架顶部，可以叠罗汉，总身高不能小于书架高度。因为多余的人会导致危险，你的任务是找到一个人的集合，使得他们的人数最少并且可以碰到书架的顶部。
> 
> 输入：
> * Line 1: Two space-separated integers: N and B
> * Lines 2..N+1: Line i+1 contains a single integer: Hi
> 第一行：两个正整数N,B
> 接下来N行：整数Hi
> 
> 输出：
> * Line 1: A single integer representing the size of the smallest set of cows that can reach the bookshelf.
> 一行：一个整数，代表最少的人数。
cow不是牛吗