Submission

Score: 90

User: Karatat007

Problemset: อนุกรม

Language: cpp

Time: 0.003 second

Submitted On: 2026-09-17 15:52:56

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

void print128(__int128 i) {
    if (i == 0) { cout << "0"; return; }
    string s;
    while (i > 0) {
        s += char('0' + (int)(i % 10));
        i /= 10;
    }
    reverse(s.begin(), s.end());
    cout << s;
}

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

    int n;
    cin >> n;
    __int128 a = 1, b = 1;
    if (n == 1 || n == 2){
        cout << 1;
    }
    for (int i = 3; i <= n; ++i){
        __int128 c = a + b;
        a = b;
        b = c;
    }
    print128(b);
}