Submission

Score: 100

User: gay69

Problemset: ผลรวมตัวเลข

Language: cpp

Time: 0.002 second

Submitted On: 2025-07-27 00:06:46

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const ll inf = 1e18;

ll solve(ll x) {
    return 2 * (((x / 2) * (x / 2 + 1)) / 2) + 3 * (((x / 3) * (x / 3 + 1)) / 2) - 6 * (((x / 6) * (x / 6 + 1)) / 2);
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    ll l, r;
    cin >> l >> r;
    cout << solve(r - 1) - solve(l - 1) << "\n";
    return 0;
}