poj2392

多重背包，多重背包可以转化为完全背包和01背包。如果某东西的总体积大于包体积，则可以当成是完全背包。否则按物品体积的1，2，4...倍分别进行01背包。这样就相当于构成了所有的可能情况，例如5 ＝ 4 ＋ 1， 7 ＝ 1 ＋ 2 ＋ 4。都可以由这些数字构成。

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      #include 
    
      <
    
      iostream
    
      >
    
      
#include 
    
      <
    
      cstdio
    
      >
    
      
#include 
    
      <
    
      cstdlib
    
      >
    
      
#include 
    
      <
    
      cstring
    
      >
    
      
#include 
    
      <
    
      algorithm
    
      >
    
      

    
      using
    
       
    
      namespace
    
       std;


    
      #define
    
       maxn 405
    
      

    
      #define
    
       maxm 40005
    
      


    
      struct
    
       Block
{
 
    
      int
    
       count, h, limit;
}block[maxn];


    
      int
    
       n;

    
      bool
    
       f[maxm];


    
      bool
    
       
    
      operator
    
       
    
      <
    
       (
    
      const
    
       Block 
    
      &
    
      a, 
    
      const
    
       Block 
    
      &
    
      b)
{
 
    
      return
    
       a.limit 
    
      <
    
       b.limit;
}


    
      void
    
       compackage(
    
      int
    
       h, 
    
      int
    
       limit)
{
 
    
      for
    
       (
    
      int
    
       i 
    
      =
    
       h; i 
    
      <=
    
      limit; i
    
      ++
    
      )
 f[i] 
    
      =
    
       f[i] 
    
      ||
    
       f[i 
    
      -
    
       h];
}


    
      void
    
       zerpackage(
    
      int
    
       h, 
    
      int
    
       limit)
{
 
    
      for
    
       (
    
      int
    
       i 
    
      =
    
       limit; i 
    
      >=
    
      h; i
    
      --
    
      )
 f[i] 
    
      =
    
       f[i] 
    
      ||
    
       f[i 
    
      -
    
       h];
}


    
      void
    
       mulpackage(
    
      int
    
       count, 
    
      int
    
       h, 
    
      int
    
       limit)
{
 
    
      if
    
       (h 
    
      *
    
       count 
    
      >=
    
       limit)
 {
 compackage(h, limit);
 
    
      return
    
      ;
 }
 
    
      int
    
       i 
    
      =
    
       
    
      1
    
      ;
 
    
      while
    
       (count 
    
      >=
    
       i)
 {
 zerpackage(h 
    
      *
    
       i, limit);
 count 
    
      -=
    
       i;
 i 
    
      <<=
    
       
    
      1
    
      ;
 }
 zerpackage(h 
    
      *
    
       count, limit);
}


    
      int
    
       main()
{
 
    
      //
    
      freopen("t.txt", "r", stdin);
    
      

    
       scanf(
    
      "
    
      %d
    
      "
    
      , 
    
      &
    
      n);
 
    
      for
    
       (
    
      int
    
       i 
    
      =
    
       
    
      0
    
      ; i 
    
      <
    
       n; i
    
      ++
    
      )
 scanf(
    
      "
    
      %d%d%d
    
      "
    
      , 
    
      &
    
      block[i].h, 
    
      &
    
      block[i].limit, 
    
      &
    
      block[i].count);
 sort(block, block 
    
      +
    
       n);
 memset(f, 
    
      0
    
      , 
    
      sizeof
    
      (f));
 f[
    
      0
    
      ] 
    
      =
    
       
    
      true
    
      ;
 
    
      for
    
       (
    
      int
    
       i 
    
      =
    
       
    
      0
    
      ; i 
    
      <
    
       n; i
    
      ++
    
      )
 mulpackage(block[i].count, block[i].h, block[i].limit);
 
    
      for
    
       (
    
      int
    
       i 
    
      =
    
       block[n 
    
      -
    
       
    
      1
    
      ].limit; i 
    
      >=
    
       
    
      0
    
      ; i
    
      --
    
      )
 
    
      if
    
       (f[i])
 {
 printf(
    
      "
    
      %d\n
    
      "
    
      , i);
 
    
      break
    
      ;
 }
 
    
      return
    
       
    
      0
    
      ;
}