Submission

Score: 100

User: RINRPTM

Problemset: โชว์ของโลมา

Language: cpp

Time: 0.004 second

Submitted On: 2026-10-03 19:22:31

#include<iostream>
using namespace std;
int main()
{
    unsigned long long x;cin>>x;
    unsigned long long sum = 0;
    unsigned long long add = 0;
    bool tf;
    if(x % 2 == 0){
        tf = 1;
        while(x > 0){
            if(tf){
                add = x*2 + (x-2);
                tf = 0;
                sum += add%10;
                sum += (add+1)%10;
            }else
            if(x != 2){
                add += x*3 + (x-2);
                sum += add%10;
                sum += (add+1)%10;
            }else{
                add += x*3 + x - 2;
                sum += add%10;
                sum += (add-1)%10;
            }
            x-=2;
        }
    }else{
        tf = 1;
        add = 0;
        while(x > 0){
            if(tf){
                add += x*2 + x -2;
                sum += add%10;
                sum += (add+1)%10;
                tf = 0;
            }else
            if(x == 1){
                add += 2;
                sum += add%10;
                x--;
                break;
            }else{
                add += x*3+x -2;
                sum += add%10;
                sum += (add+1)%10;
            }
            x -= 2;
        }
    }
    cout << sum;
}