Submission

Score: 100

User: angpangSK

Problemset: อนุกรม

Language: cpp

Time: 0.004 second

Submitted On: 2025-09-23 20:39:59

#include <iostream>
using namespace std;

long long fibonacci(int n) {
    if (n == 1 || n == 2) return 1;

    long long a = 1, b = 1, c;
    for (int i = 3; i <= n; i++) {
        c = a + b;
        a = b;
        b = c;
    }
    return b;
}

int main() {
    int n;
    cin >> n;
    cout << fibonacci(n);
}