Submission

Score: 70

User: cyblox_boi

Problemset: Fibonacci Croissant

Language: cpp

Time: 0.003 second

Submitted On: 2026-01-01 01:59:00

#include <bits/stdc++.h>
using namespace std;

long long fibo(int at)
{
    double a = (1 + sqrt(5)) / 2;
    double b = (1 - sqrt(5)) / 2;
    long long fib = (1 / sqrt(5)) * (pow(a, at) - pow(b, at));

    return fib;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n;
    cin >> n;

    long long result = 0;

    for (int i = 0; i <= n; i++)
    {
        result += fibo(i);
    }

    cout << result << '\n';

    return 0;
}