Submission #858007

#	Time	Username	Problem	Language	Result	Execution time	Memory
858007		danikoynov	Diversity (CEOI21_diversity)	C++14	64 / 100	76 ms	16060 KiB

diversity

#include<bits/stdc++.h>
#define endl '\n'

using namespace std;
typedef long long ll;

void speed()
{
    ios_base::sync_with_stdio(NULL);
    cin.tie(NULL);
    cout.tie(NULL);
}

const int maxn = 3e5 + 10;

int n, q, a[maxn], cnt[maxn], m;
ll bef[maxn], aft[maxn], pref[maxn];
const ll inf = 1e18;
vector < ll > groups;
ll val[maxn];

void solve()
{
    cin >> n >> q;
    for (int i = 1; i <= n; i ++)
        cin >> a[i];

    int l, r;
    cin >> l >> r;

    for (int i = 1; i <= n; i ++)
        cnt[a[i]] ++;


    for (int i = 1; i <= n; i ++)
        if (cnt[i] > 0)
            groups.push_back((ll)(cnt[i]));

    m = groups.size();
    sort(groups.begin(), groups.end());
    reverse(groups.begin(), groups.end());
    l = (m + 1) / 2;
    r = (m + 1) / 2;
    val[l] = groups[0];
    for (int i = 1; i < m; i ++)
    {
        if (l == 1)
        {
            val[++ r] = groups[i];
        }
        else if (r == n)
        {
            val[-- l] = groups[i];
        }
        else
        {
            if (i % 2 == 1)
            {
                val[++ r] = groups[i];
            }
            else
            {
                val[-- l] = groups[i];
            }
        }
    }


    ll tot = 0;
    ll bf = 0;
    for (int i = 1; i <= m; i ++)
    {
        bef[i] = bf;
        bf += val[i];
    }
    ll af = 0;
    for (int i = m ; i > 0; i --)
    {
        aft[i] = af;
        af += val[i];
    }

    for (ll i = 1; i <= m; i ++)
    {
        tot = tot + i * val[i] * (bef[i] - aft[i]);
    }

    ll sf = 0;
    for (int i = 1; i <= m; i ++)
    {
        ll cur = val[i];
        tot = tot + cur * (cur + 1) / 2;
        tot = tot + val[i] * sf;
        sf += val[i];
    }

    cout << tot << endl;
}

int main()
{
    solve();
    return 0;
}
/**
4 1
1 1 1 1
1 2
2 4

4 1
2 1 3 2
1 4

*/

• Subtask 1: 4 / 4
• Subtask 2: 10 / 10
• Subtask 3: 8 / 8
• Subtask 4: 16 / 16
• Subtask 5: 26 / 26
• Subtask 6: 0 / 36