Submission

PPPPPPPPPP

Score: 100

User: Nightingale

Problemset: โชว์ของโลมา

Language: cpp

Time: 0.002 second

Submitted On: 2025-03-31 21:04:12

#include <bits/stdc++.h>
#define int long long
using namespace std;
int32_t main() 
{
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int a;
  cin >> a;
  if(a==1){
    cout << 1;
    return 0;
  }
  if(a==2){
    cout << 7;
    return 0;
  }
  int sum = (3*a-2)%10;
  int current = 3*a-2;
  int interval = 4*(a-3)+2;
  int credit = 0;
  sum = sum+(sum+1)%10;
  while(interval>0){
    current+=interval;
    sum = sum+(current)%10;
    if(interval>=8){
      sum = sum+(current+1)%10;
    }
    interval-=8;
  }
  if(a%2==0) cout << sum+(current-1)%10;
  else cout << sum;
}