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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
这题我是先会的一维的，想明白了，再去看背包问题，结果发现用而二维的做会少，其实还是代码没写对
这题用二维做会MLE，它的意思就是要你用一维去做，不过我把二维一维的都写上来
一维
#include<queue> #include<math.h> #include<stdio.h> #include<string.h> #include<string> #include<iostream> #include<algorithm> using namespace std; #define N 1234567 #define M 12 int f[N]; int w[N]; int d[N]; int n,m; int main() { while(~scanf("%d %d",&n,&m)) { for(int i=1;i<=n;i++) scanf("%d%d",&w[i],&d[i]); memset(f,0,sizeof(f)); for(int j=1;j<=n;j++) { for(int i=m;i>=0;i--) { if(i>=w[j]) f[i]=max(f[i],f[i-w[j]]+d[j]); } } cout<<f[m]<<endl; } return 0; } /* 4 6 1 4 2 6 3 12 2 7 */
二维
#include<queue> #include<math.h> #include<stdio.h> #include<string.h> #include<string> #include<iostream> #include<algorithm> using namespace std; #define N 12888 #define M 12 int f[N]; int g[4000][N]; int w[N]; int d[N]; int n,m; int main() { while(~scanf("%d %d",&n,&m)) { for(int i=1;i<=n;i++) scanf("%d%d",&w[i],&d[i]); memset(g,0,sizeof(g)); for(int i=1;i<=n;i++) { for(int v=m;v>=0;v--) { g[i][v]=g[i-1][v];//开始就是少了这一句老是不对 if(v>=w[i]) g[i][v]=max(g[i-1][v],g[i-1][v-w[i]]+d[i]); } } cout<<g[n][m]<<endl; } return 0; } /* 4 6 1 4 2 6 3 12 2 7 */
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原文地址：http://www.cnblogs.com/wmxl/p/4743825.html
