hdu 1028 整数划分 （母函数）

假如输入4
4 = 4;
4 = 3 + 1;
4 = 2 + 2;
4 = 2 + 1 + 1;
4 = 1 + 1 + 1 + 1;
一共5种

假如输入3 用母函数的方法就是写成
（1+X+X2+X3）(1+X2)(1+X3) 展开后 求X3的系数

假如输入n
就是（1+X+X2+X3+X4....）(1+X2+X4+X6..)(1+X3+X6...)(....)

Sample Input
4
10
20

Sample Output
5
42
627

 # include <iostream>
 # include <cstdio>
 # include <cstring>
 # include <algorithm>
 # include <string>
 # include <cmath>
 # include <queue>
 # include <list>
 # define LL long long
 using namespace std ;

 int c1[], c2[] ;
 int main()
 {
     //freopen("in.txt","r",stdin) ;
     int n;
     int i, j, k;
     while(cin >> n)
     {
         for(i=; i<=n; ++i)
         {
             c1[i] = ;
             c2[i] = ;
         }
         for(i=; i<=n; ++i)
         {

             for(j=; j<=*n; ++j)
                 for(k=; k <= *n; k += i)
                 {
                     c2[j+k] += c1[j];
                 }
                 for(j=; j<=n; ++j)
                 {
                     c1[j] = c2[j];
                     c2[j] = ;
                 }
         }
         cout << c1[n] << endl;
     }
     return ;
 }