hdu1059 Dividing（多重背包+二进制优化）

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花了也有一段时间理解背包模板和二进制转化，既然普通法做多重背包容易超时，不妨每个都用二进制优化。二进制优化按照2的次幂分堆，每次处理一堆，但因为用while每次乘2是跑完背包乘的，所以需要再跑一次背包。再有就是学到位运算的乘2，感觉有点收获。

#include <stdio.h>#include <math.h>#include <algorithm>#include <cmath>using namespace std;const int N = 100005;int sum;int dp[N];void ZeroOnePack(int cost, int weight){    for(int i = sum; i >= cost; i --)        dp[i] = max(dp[i], dp[i - cost] + weight);}void CompletePack(int cost, int weight){    for(int i = cost; i <= sum; i ++)        dp[i] = max(dp[i], dp[i - cost] + weight);}void MulPack(int cost, int weight, int countt){    if(cost * countt >= sum) //如果背包能满    {        CompletePack(cost, weight);        return;    }    int i = 1;    while(i < countt)    {        ZeroOnePack(i * cost, i * weight);        countt -= i;        i <<= 1;    }    ZeroOnePack(countt * cost, countt * weight);}int main(){  //  freopen("in.txt", "r", stdin);    int a[N], Case = 1;    while(1)    {        sum = 0;        for(int i = 1; i <= 6; i ++)        {            scanf("%d", &a[i]);            sum += (a[i] * i);        }        if(!sum) break;        printf("Collection #%d:\n", Case ++);        if(sum % 2 == 1) printf("Can't be divided.\n\n");        else        {            sum /= 2;            for(int i = 0; i <= sum; i ++) dp[i] = 0;            for(int i = 1; i <= 6; i ++)            {                if(a[i]) MulPack(i, i, a[i]);            }            if(dp[sum] == sum) printf("Can be divided.\n\n");            else printf("Can't be divided.\n\n");        }    }    return 0;}

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