poj 2392 多重背包

题意：有几个砖，给出高度，能放的最大高度和数目，求这些砖能垒成的最大高度

依据lim排个序，按一层一层进行背包

 #include<cstdio>
 #include<iostream>
 #include<algorithm>
 #include<cstring>
 #include<cmath>
 #include<queue>
 using namespace std;
 const int maxn=;
 int n,m,t;
 int dp[maxn];
 struct Node
 {
     int h,c;
     int l;
     void input()
     {
         scanf("%d%d%d",&h,&l,&c);
     }
 }node[maxn];
 bool cmp(Node a,Node b)
 {
     return a.l<b.l;
 }
 //0-1背包，代价为cost,获得的价值为weight
 void ZeroOnePack(int cost,int weight,int lim)
 {
     for(int i=lim;i>=cost;i--)
       dp[i]=max(dp[i],dp[i-cost]+weight);
 }

 //完全背包，代价为cost,获得的价值为weight
 void CompletePack(int cost,int weight,int lim)
 {
     for(int i=cost;i<=lim;i++)
       dp[i]=max(dp[i],dp[i-cost]+weight);
 }

 //多重背包
 void MultiplePack(int cost,int weight,int amount,int lim)
 {
     if(cost*amount>=lim) CompletePack(cost,weight,lim);
     else
     {
         int k=;
         while(k<amount)
         {
             ZeroOnePack(k*cost,k*weight,lim);
             amount-=k;
             k<<=;
         }
         ZeroOnePack(amount*cost,amount*weight,lim);//这个不要忘记了，经常掉了
     }
 }
 int main()
 {
     int i,j,k;
     #ifndef ONLINE_JUDGE
     freopen("1.in","r",stdin);
     #endif
     while(scanf("%d",&n)!=EOF)
     {
         for(i=;i<n;i++)    node[i].input();
         sort(node,node+n,cmp);
         memset(dp,,sizeof(dp));
         for(i=;i<n;i++)
         {
             MultiplePack(node[i].h,node[i].h,node[i].c,node[i].l);
         }
         int maxh=node[n-].l;
         int ans=;
         for(i=;i<=maxh;i++)
         {
             ans=max(dp[i],ans);
         }
         printf("%d",ans);
     }
     return ;
 }