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 i in the supplied list has a weight Wi (1 ≤ Wi ≤ 400), a 'desirability' factor Di (1 ≤ Di ≤ 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.
Input
* Line 1: Two space-separated integers: N and M
* Lines 2..N+1: Line i+1 describes charm i with two space-separated integers: Wi and Di
Output
* Line 1: A single integer that is the greatest sum of charm desirabilities that can be achieved given the weight constraints
Sample Input
4 6 1 4 2 6 3 12 2 7
Sample Output
23
解题报告：
又水了一道题目，这是一道裸的01背包问题，可是我又把数组开小了。。。。
ac代码：
#include<cstdio>
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#include<cstring>
#include<queue>
#include<stack>
using namespace std;
int w[3500],val[3500];
int dp[20000];
int main()
{int n,m;scanf("%d%d",&n,&m);for(int i=0;i<n;i++)scanf("%d%d",&w[i],&val[i]);for(int i=0;i<n;i++){for(int j=m;j>=w[i];j--){dp[j]=max(dp[j],dp[j-w[i]]+val[i]);}}printf("%d\n",dp[m]);return 0;
}