Submission

PPPPPPPPPP

Score: 100

User: dwad2

Problemset: โชว์ของโลมา

Language: cpp

Time: 0.002 second

Submitted On: 2025-03-19 01:20:48

#include <bits/stdc++.h>

using namespace std;

long long findleft(int n, long long s) {
    s += 3 * (n - 1);
    return s % 10;
}

int main() {

    int n;
    cin >> n;
    int sum = 0;
    long long s = 1;

    while(n > 2) {
        sum += findleft(n, s);
        sum += (findleft(n, s) + 1) % 10;
        s += 4 * (n - 1);
        n -= 2;
    }

    if(n == 1) {
        sum += s % 10;
    }
    else if(n == 2) {
        sum += (s + 2) % 10;
        sum += (s + 3) % 10;
    }

    cout << sum;

    return 0;
}