P2871 [USACO07DEC]手链Charm Bracelet

题目描述

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 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.

有N件物品和一个容量为V的背包。第i件物品的重量是c[i]，价值是w[i]。求解将哪些物品装入背包可使这些物品的重量总和不超过背包容量，且价值总和最大。

输入输出格式

输入格式：

• 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

输出格式：

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

输入输出样例

输入样例#1：

4 6
1 4
2 6
3 12
2 7

输出样例#1：

23

虽然是裸的背包，但是这个不能用二维，会爆
然后自己手推了一下一维的，，
貌似还能更短。。。

 #include<iostream>
 #include<cstdio>
 #include<cstring>
 #include<cmath>
 using namespace std;
 void read(int & n)
 {
     char c='+';int x=;int flag=;
     while(c<''||c>'')
     {
         c=getchar();
         if(c=='-')
         flag=;
     }
     while(c>=''&&c<='')
     x=x*+(c-),c=getchar();
     flag==?n=-x:n=x;
 }
 const int MAXN=;
 int n,maxt;
 struct node
 {
     int w;
     int v;
 }a[MAXN];
 int dp[MAXN];
 int main()
 {
     read(n);read(maxt);
     for(int i=;i<=n;i++)
     {
         read(a[i].w);read(a[i].v);
     }
     for(int i=;i<=n;i++)
     {
         for(int j=maxt;j>=;j--)
         {
             if(a[i].w<=j)
             dp[j]=max(dp[j],dp[j-a[i].w]+a[i].v);
             else
             dp[j]=dp[j];
         }
     }
     cout<<dp[maxt];
     return ;
 }