hdu 1059 多重背包

题意：价值分别为1，2，3，4，5，6的物品个数分别为a[1],a[2],a[3],a[4],a[5],a[6],问能不能分成两堆价值相等的。

解法：转化成多重背包

#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<iostream>
using namespace std;

int dp[120010];
int a[10];

int nValue;

//0-1背包，代价为cost,获得的价值为weight
void ZeroOnePack(int cost,int weight)
{
    for(int i=nValue;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)
{
    for(int i=cost;i<=nValue;i++)
      dp[i]=max(dp[i],dp[i-cost]+weight);
}

//多重背包
void MultiplePack(int cost,int weight,int amount)
{
    if(cost*amount>=nValue) CompletePack(cost,weight);
    else
    {
        int k=1;
        while(k<amount)
        {
            ZeroOnePack(k*cost,k*weight);
            amount-=k;
            k<<=1;
        }
        ZeroOnePack(amount*cost,amount*weight);//这个不要忘记了，经常掉了
    }
}

int main()
{
    int iCase=0;
    while(1)
    {
        iCase++;
        int tol=0;
        for(int i=1;i<=6;i++)
        {
            scanf("%d",&a[i]);
            tol+=i*a[i];
        }
        if(tol==0)break;
        printf("Collection #%d:
",iCase);
        if(tol%2!=0)
        {
            printf("Can't be divided.

");
            continue;
        }
        else
        {
            nValue=tol/2;

        }
        memset(dp,0,sizeof(dp));
        for(int i=1;i<=6;i++)
          MultiplePack(i,i,a[i]);
        if(dp[nValue]==nValue)printf("Can be divided.

");
        else printf("Can't be divided.

");
    }
    return 0;
}