Submission

Score: 70

User: C12

Problemset: โชว์ของโลมา

Language: cpp

Time: 0.003 second

Submitted On: 2025-12-30 14:39:07

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

#define f first
#define s second
#define pii pair<ll,ll>
#define puii pair<ull,ull>
#define piii pair<ll,pii>
#define ll long long
#define ull unsigned long long
#define mp make_pair
 
#define mpiii(a,b,c) make_pair(a,make_pair(b,c));
ll mod = 1000000007;

int frame(int n,int start){

    if(n <= 0) return 0;

    ull end = start + (n*2 % 10);
    ull unit = 0;
    unit += (end + (n-2)) % 10;
    if(n-2 == 0){
        unit += (end + (n-2) - 1) % 10;
    }
    else{
        unit += (end + (n-2) + 1) % 10;
    }

    // cout << n << ' ' << ((end + (n-2)) % 10) << ' ' << ((end + (n-2) + 1) % 10);
    end += ((n-2)*2 % 10);
    end %= 10;

    // cout << end << '\n';

    return unit + frame(n-2,end);
}

void solve(){
    ull n;

    cin >> n;

    
    cout << frame(n,0);

    return;
}
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);

    ll q;
 
    // cin >> q;

    // while(q--) 
    
    solve();

    return 0;
}