4131：Charm Bracelet，考点：动规，滚动数组节省空间

原题：http://bailian.openjudge.cn/practice/4131/

描述

Bessie has gone to the mall‘s jewelry store and spies a charm bracelet. Of course, she‘d like to fill it with the best charms possible from the N(1 ≤ N≤ 3,402) available charms. Each charm iin the supplied list has a weight W_i(1 ≤ W_i≤ 400), a ‘desirability‘ factor D_i(1 ≤ D_i≤ 100), and can be used at most once. Bessie can only support a charm bracelet whose weight is no more than M(1 ≤ M≤ 12,880).

Given that weight limit as a constraint and a list of the charms with their weights and desirability rating, deduce the maximum possible sum of ratings.

（这么长的英文我也懒得看）

有N见物品和一个容积为M的背包，第i件物品的重量w[i]，价值为d[i]，求解将哪些物品放入背包可使价值总和最大，每种物品只有一件，可以选择放或者不放。

输入

Line 1: Two space-separated integers: N and M
Lines 2..N+1: Line i+1 describes charm i with two space-separated integers: W_i and D_i

输出

Line 1: A single integer that is the greatest sum of charm desirabilities that can be achieved given the weight constraints

样例输入

4 6
1 4
2 6
3 12
2 7