1014 Dividing 多重背包

#include <iostream>#include <cstring>using namespace std;int n[7];  //价值为i的物品的个数int v;  //背包容量int SumValue;  //物品总价值bool flag;    //标记是否能平分SumValueint dp[100000];  //状态数组int max(int a,int b){    return a>b?a:b;}/*完全背包*/void CompletePack(int cost,int weight){    for(int i=cost;i<=v;i++)    {        dp[i]=max(dp[i],dp[i-cost]+weight);        if(dp[i]==v)    //剪枝，当能够平分SumValue时退出        {            flag=true;            return;        }    }    return;}/*01背包*/void ZeroOnePack(int cost,int weight){    for(int i=v;i>=cost;i--)    {        dp[i]=max(dp[i],dp[i-cost]+weight);        if(dp[i]==v)    //剪枝        {            flag=true;            return;        }    }    return;}/*多重背包*/void MultiplePack(int cost,int weight,int amount){    if(cost*amount>=v)    {        CompletePack(cost,weight);        return;    }    if(flag)    //剪枝        return;    /*二进制优化*/    int k=1;    while(k<amount)    {        ZeroOnePack(k*cost,k*weight);        if(flag)    //剪枝            return;        amount-=k;        k*=2;    }    ZeroOnePack(amount*cost,amount*weight);    return;}int main(){    int test=1;    while(cin>>n[1]>>n[2]>>n[3]>>n[4]>>n[5]>>n[6])    {        SumValue=0;  //物品总价值        for (int i=1; i<=6; i++)            SumValue+=i*n[i];        if (SumValue==0)            break;        if (SumValue%2)    //sum为奇数，无法平分        {            cout<<"Collection #"<<test++<<':'<<endl;            cout<<"Can't be divided."<<endl<<endl;    //注意有空行            continue;        }        v=SumValue/2;        memset(dp,-1,sizeof(dp));        dp[0]=0;        flag=false;        for(int i=1; i<=6; i++)        {            MultiplePack(i,i,n[i]);            if(flag)    //剪枝                break;        }        if(flag)        {            cout<<"Collection #"<<test++<<':'<<endl;            cout<<"Can be divided."<<endl<<endl;            continue;        }        else        {            cout<<"Collection #"<<test++<<':'<<endl;            cout<<"Can't be divided."<<endl<<endl;            continue;        }    }    return 0;}