HDU 2802 F(N) [Ad Hoc]

Description

Algorithm

Hint

Code

#include <cmath>
#include <iostream>
using namespace std;
const int maxn = 5000;
const int kmod = 2009;
int main()
{
int a[maxn] = {0, 1, 7};
long long t;
for (int i = 3; i < maxn; i++)
{
a[i] = (a[i - 2] - ((i - 1) * (i - 1) * (i - 1)) + (i * i * i)) % kmod;
if (a[i] == 1)
{
t = i - 1;
}
}
long long n;
for (;;)
{
cin >> n;
if (n == 0) break;
if (n % t == 0) cout << a[t]; else cout << a[n % t];
cout << endl;
}
return 0;
}