Submission

Score: 100

User: mantaggez

Problemset: โชว์ของโลมา

Language: cpp

Time: 0.002 second

Submitted On: 2026-03-22 18:40:37

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

ll n;

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin >> n;

    // vector<ll> res;
    ll i = 0, j = 0, ans = 0;
    while(i < n * n)
    {
        ll a = max(0LL, n - j);
        ll b = max(0LL, n - j - 2);
        i += (2 * a + b);
        // cout << i << '\n';
        if(i > n * n) {
            ans += ((i - 1) % 10);
            // res.push_back((i - 1) % 10);
            break;
        }

        if(i == n * n)  {
            ans += (i % 10) + ((i - 1) % 10);
            // res.push_back(i % 10);
            // res.push_back((i - 1) % 10);
            break;
        }
        ans += (i % 10) + ((i + 1) % 10);
        // res.push_back(i % 10);
        // res.push_back((i + 1) % 10);
        i += b;
        j += 2;
    }

    // for(ll it : res) cout << "res : " << it << '\n'; cout << '\n';
    cout << ans << '\n';

    return 0;
}