hdu 1171 Big Event in HDU（母函数or多重背包）

//母函数 1103ms:

 

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define MAXN 250001

bool c1[MAXN], c2[MAXN];
int value[MAXN], num[MAXN];

void genfun(const int amount, const int sum)
{
    memset(c1, 0, sizeof(*c1) * sum);
    memset(c2, 0, sizeof(*c2) * sum);
    c1[0] = 1;

    int i, j, k;
    for(i = 0; i < amount; i++)
    {
        for(j = 0; j <= sum; j++)
        {
            for(k = 0; (k <= num[i]) && (value[i] * k + j <= sum); k++)
            {
             //   c2[value[i] * k + j] += c1[j];
                if(c1[j]) c2[value[i] * k + j] = 1;
            }
        }
        for(j = 0; j <= sum; j++)
        {
            c1[j] = c2[j];
            c2[j] = 0;
        }
    }
}

int main()
{
    #ifndef ONLINE_JUDGE
    freopen("indata.txt", "r", stdin);
    #endif
    int n;
    while(scanf("%d", &n), n > 0)
    {
        int i, sum = 0;
        for(i = 0; i < n; i++)
        {
            scanf("%d %d", &value[i], &num[i]);
            sum += value[i] * num[i];
        }
        genfun(n, sum);
  //      for(i = 0; i <= sum; i++) printf("%d ", c1[i]); printf("\n");
        for(i = sum / 2; i >= 0; i--)
        {
            if(c1[i])
            {
                printf("%d %d\n", sum - i, i);
                break;
            }
        }
    }
    return 0;
}

 

 

//多重背包 43ms:

 

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAXN 55
#define MAXM 250001

int aver, value[MAXN], num[MAXN];
int f[MAXM];

inline int getMax(int a, int b)
{
    return a > b ? a : b;
}

void ZeroOnePack(int w, int v)
{
    for(int j = aver; j >= w; j--)
    {
        f[j] = getMax(f[j], f[j - w] + v);
    }
}
void CompletePack(int w, int v)
{
    for(int j = w; j <= aver; j++)
    {
        f[j] = getMax(f[j], f[j - w] + v);
    }
}
void MultiplePack(int w, int v, int amount)
{
    if(amount * w >= aver)
    {
        CompletePack(w, v);
        return;
    }
    int k = 1;
    while(k < amount)
    {
        ZeroOnePack(k * w, k * v);
        amount -= k;
        k <<= 1;
    }
    ZeroOnePack(amount * w, amount * v);
}

int main()
{
#ifndef ONLINE_JUDGE
    freopen("indata.txt", "r", stdin);
#endif
    int n;
    while(scanf("%d", &n), n > 0)
    {
        int i = 0, sum = 0;
        for(i = 1; i <= n; i++)
        {
            scanf("%d %d", &value[i], &num[i]);
            sum += value[i] * num[i];
        }
        aver = sum >> 1;
        memset(f, 0, sizeof(*f) * (aver + 1));
        for(i = 1; i <= n; i++) MultiplePack(value[i], value[i], num[i]);
        int theMax = f[aver];
        if(theMax < sum - theMax) theMax = sum - theMax;
        printf("%d %d\n", theMax, sum - theMax);
    }
    return 0;
}