hdu 1171 母函数

Problem Description
Nowadays, we all know that Computer College is the biggest department in HDU. But, maybe you don’t know that Computer College had ever been split into Computer College and Software College in 2002.
The splitting is absolutely a big event in HDU! At the same time, it is a trouble thing too. All facilities must go halves. First, all facilities are assessed, and two facilities are thought to be same if they have the same value. It is assumed that there is N (0

题解：

    母函数模板。这里用到一个贪心思想，当我们计算出所有组合数后，由于题目要求两个College人数尽量可能相等。应从中间开始往一边枚举，输出即可。

代码：

#include 
#include 
using namespace std;
const int maxn = 500000;
int v[51],n[101];
int num,i,j,k,last,last2,a[maxn],b[maxn];

int main()
{
    while(cin>>num&&num>0)
    {
        for(int i=0;icin>>v[i]>>n[i];
        a[0]=1;
        last=0;
    for (i=0;imemset(b,0,sizeof(int)*(last2+1));
    for ( j=0;j<=n[i];j++)
        for ( k=0;k<=last;k++)
            b[k+j*v[i]]+=a[k];
    memcpy(a,b,sizeof(int)*(last2+1));
    last=last2;
   }
    for(i=last/2;i>=0;i--){
            if(a[i]){
      cout<' '<break;
      }
}
    }
    return 0;
}