Description：

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

程序代码：  

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define N 100001
int dp[N],w[N],v[N];
int main()
{
  int n,m;
  scanf("%d %d",&n,&m);
  memset(dp,0,sizeof(dp));
  for(int i=0;i<n;i++)
    scanf("%d %d",&v[i],&w[i]);
  for(int i=0;i<n;i++)
  {
    for(int j=m;j>=v[i];j--)
    {
      dp[j]=max(dp[j],dp[j-v[i]]+w[i]);
    }
  }
  printf("%d\n",dp[m]);
  return 0;
}