Problem I: Ingenuous Cubrency

Your task is to count the number of ways to pay a given amount using cubic coins of Cubeland. For example, there are 3 ways to pay 21 cubes: twenty one 1cube coins, or one 8 cube coin and thirteen 1 cube coins, or two 8 cube coin and five 1 cube coins.
Input consists of lines each containing an integer amount to be paid. You may assume that all the amounts are positive and less than 10000.
For each of the given amounts to be paid output one line containing a single integer representing the number of ways to pay the given amount using the coins available in Cubeland.
Sample input
10 21 77 9999
Output for sample input
2 3 22 440022018293--------------------
-------------------
#include <iostream> #include <cstdio> #include <cstring> using namespace std; long long a[33]; long long f[11111]; int n; int main() { for (int i=1;i<=21;i++) { a[i]=i*i*i; } while (~scanf("%d",&n)) { memset(f,0,sizeof(f)); f[0]=1; for (int i=1;i<=21;i++) { for (int j=0;j<=n-a[i];j++) { if (f[j]) f[j+a[i]]+=f[j]; } } printf("%lld\n",f[n]); } return 0; }