poj2392 多重背包

 1 //Accepted    868 KB    188 ms
 2 //多重背包
 3 #include <cstdio>
 4 #include <cstring>
 5 #include <iostream>
 6 #include <queue>
 7 #include <cmath>
 8 #include <algorithm>
 9 using namespace std;
10 /**
11   * This is a documentation comment block
12   * 如果有一天你坚持不下去了，就想想你为什么走到这儿！
13   * @authr songt
14   */
15 const int imax_v = 40005;
16 const int imax_n = 405;
17 int dp[imax_v];
18 int n;
19 struct node
20 {
21     int weight,c,a;
22 }f[imax_n];
23 //按a排序，考虑我们在dp时采用的是倒推，所以我们需要先计算出a较小的时候的情况
24 int cmp(node x,node y)
25 {
26     return x.a<y.a;
27 }
28 int max(int a,int b)
29 {
30     return a>b?a:b;
31 }
32 void zeroOnePack(int weight,int value,int v)
33 {
34     for (int j=v;j>=weight;j--)
35     {
36         dp[j]=max(dp[j],dp[j-weight]+value);
37     }
38 }
39 void completePack(int weight,int value,int v)
40 {
41     for (int j=weight;j<=v;j++)
42     {
43         dp[j]=max(dp[j],dp[j-weight]+value);
44     }
45 }
46 void multiplePack(int weight,int value,int amount,int v)
47 {
48     int k=1;
49     if (amount*weight>=v)
50     {
51         completePack(weight,value,v);
52         return ;
53     }
54     while (k<amount)
55     {
56         zeroOnePack(k*weight,k*value,v);
57         amount-=k;
58         k<<=1;
59     }
60     zeroOnePack(amount*weight,amount*value,v);
61 }
62 void Dp()
63 {
64     memset(dp,0,sizeof(dp));
65     for (int i=1;i<=n;i++)
66     {
67         multiplePack(f[i].weight,f[i].weight,f[i].c,f[i].a);
68     }
69     int ans=0;
70     for (int i=1;i<=40000;i++)
71     ans=max(ans,dp[i]);
72     printf("%d\n",ans);
73 }
74 int main()
75 {
76     while (scanf("%d",&n)!=EOF)
77     {
78         for (int i=1;i<=n;i++)
79         scanf("%d%d%d",&f[i].weight,&f[i].a,&f[i].c);
80         sort(f+1,f+n+1,cmp);
81         Dp();
82     }
83     return 0;
84 }