提出 #54100050

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ソースコード 拡げる

/// I am snatchin chains and burnin' tattoos
#include <bits/stdc++.h>
using namespace std;

#define pb push_back
#define F first
#define S second
#define f(i, a, b) for (int i = a; i < b; i++)
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define sz(x) (int)(x).size()
#define mp(x, y) make_pair(x, y)
#define popCnt(x) (__builtin_popcountll(x))
#define int ll

using ll = long long;
using ii = pair<int, int>;
using ull = unsigned long long;

const int N = 1e6 + 5, A = 26 * 26, LG = 19, MOD = (119 << 23) + 1;
const long double PI = acos(-1);
const long double EPS = 1e-7;
int cnt[N];
void doWork() {

    int n;
    cin >> n;
    f(i, 0, n) {
        int x;
        cin >> x;
        cnt[x] += 1;
    }
    int ans = 0;
    f(i, 1, N) cnt[i] += cnt[i - 1];
    for (int i = 1; i < N; i++)
    {
        int cur = cnt[i] - cnt[i - 1];
        ans -= cur * cur;
        ans += cur * (cur - 1) / 2;
        for (int j = 1; i * j < N; j++) {
            int add = cnt[min(N - 1, i * j + i - 1)] - cnt[i * j - 1];
            ans += cur * j * add;
        }

    }
    cout << ans << endl;

}


int32_t main() {
#ifdef LOCAL
    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);
#else
    ios_base::sync_with_stdio(0);
    cin.tie(0);
#endif

    int t = 1;
    // cin >> t;
    while (t--) {
        doWork();
    }
}

提出情報

ジャッジ結果