多重背包 （poj 1014）

　题目：Dividing

　题意：6种重量的的石头，每个给定数量，用总重的一半去装，问能否装满.

#include <iostream>
#include <algorithm>
#include <stdlib.h>
#include <time.h>
#include <cmath>
#include <cstdio>
#include <string>
#include <cstring>
#include <vector>
#include <queue>
#include <stack>
#include <set>

#define c_false ios_base::sync_with_stdio(false); cin.tie(0)
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3f
#define zero_(x,y) memset(x , y , sizeof(x))
#define zero(x) memset(x , 0 , sizeof(x))
#define MAX(x) memset(x , 0x3f ,sizeof(x))
#define swa(x,y) {LL s;s=x;x=y;y=s;}
using namespace std ;
#define N 20005

const double PI = acos(-1.0);
typedef long long LL ;
int dp[6*N];
int i = 0;
int W,a[10];
void ZeroOnePack(int siz, int prise){
    for(int i = W;i>=siz;i--)
        dp[i] = max(dp[i], dp[i-siz] + prise);
}

void CompletePack(int siz, int prise){
    for(int i = siz; i<= W; i++)
        dp[i] = max(dp[i], dp[i-siz]+prise);
}

void MultiplePack(int siz, int prise, int num){
    if(siz*num >= W){
        CompletePack(siz,prise);
        return ;
    }
    int k = 1;
    while(k<num){
        ZeroOnePack(k*siz, k*prise);
        num-=k;
        k*=2;
    }
    ZeroOnePack(num*siz, num*prise);
}

bool cal(){
    if(W%2 == 0) W/=2;
    else return false;
    for(int i =1 ; i <= 6; i++ ){
        MultiplePack(i,i,a[i]);
    }
    if(dp[W] == W)
        return true;
    else
        return false;
}

int main(void){
    //freopen("in.txt","r",stdin);
    while(cin>>a[1]>>a[2]>>a[3]>>a[4]>>a[5]>>a[6]){
        zero(dp);
        W = 0;
        for(int j = 1;j <= 6;j++){
            W+=j*a[j];
        }
        if(a[6]== 0 &&a[1] == 0 &&a[2] == 0&& a[3] == 0&& a[4] ==0&& a[5] ==0)
            break;
        printf("Collection #%d:\n",++i);
        if(cal())
            puts("Can be divided.\n");
        else
            puts("Can‘t be divided.\n");
    }
    return 0;
}