| Time Limit: 1000MS | Memory Limit: 65536K | |
| Total Submissions: 23025 | Accepted: 10358 |
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
题意：01背包
重点：01背包、动态规划
难点：动态方程
#include<cstdio>
#include<cstring>
int main()
{
int n,s,i,j,v[40000],w[40000],dp[40000];
while(scanf("%d%d",&n,&s)==2)
{
memset(v,0,sizeof(v));
memset(w,0,sizeof(w));
memset(dp,0,sizeof(dp));
for(i=1;i<=n;i++)
{
scanf("%d%d",&w[i],&v[i]);
}
for(i=1;i<=n;i++)
for(j=s;j>=w[i];j--)
{
if(dp[j]<dp[j-w[i]]+v[i])
dp[j]=dp[j-w[i]] + v[i] ;
}
printf("%d\n",dp[s]);
}return 0;
}
![洛谷P2871-[USACO07DEC]Charm Bracelet S（01背包模板题）](https://ucc.alicdn.com/images/user-upload-01/20200725131735571.png?x-oss-process=image/resize,h_160,m_lfit)