Submission #799720

#	Time	Username	Problem	Language	Result	Execution time	Memory
799720		Johann	Diversity (CEOI21_diversity)	C++14	100 / 100	1759 ms	7932 KiB

diversity

#include "bits/stdc++.h"
using namespace std;

typedef long long ll;
typedef vector<ll> vi;
typedef pair<ll, ll> pii;
typedef vector<pii> vpii;
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()

const ll INF = 1e18;
int N, Q;
int A[300007];
ll ans[50005];
int freq[300007];
int cnt[300007];
unordered_set<int> S;
int stuff[300007];
int idx;
ll tmp;
int pref, suff, n;

struct query
{
    int l, r, idx;
};

ll totalLengthOfSubsequences(ll x)
{
    return x * (x + 1) * (x + 2) / 6;
}
void doStuff(ll x, ll y)
{
    ll len = x * y;

    // if both are in set
    tmp += x * x * (totalLengthOfSubsequences(y) - y) + y * x * (x + 1) / 2;
    // if one is inside the other isn't
    tmp += (n - len) * (x * y * (y + 1) / 2);
    // if both are outside
    tmp += y * pref * (n - pref - len);

    pref += len;
    swap(pref, suff);
}
void add(int x)
{
    if (freq[x] > 0)
        --cnt[freq[x]];
    ++freq[x];
    ++cnt[freq[x]];
    if (cnt[freq[x]] == 1)
        stuff[idx++] = freq[x];
}
void sub(int x)
{
    --cnt[freq[x]];
    --freq[x];
    if (freq[x])
    {
        ++cnt[freq[x]];
        if (cnt[freq[x]] == 1)
            stuff[idx++] = freq[x];
    }
}

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

    cin >> N >> Q;
    for (int i = 0; i < N; ++i)
        cin >> A[i];

    vector<query> Qu(Q);
    for (int i = 0; i < Q; ++i)
        cin >> Qu[i].l >> Qu[i].r, Qu[i].idx = i, --Qu[i].l;

    int sq = ceil(sqrt(N));
    auto cmp = [&](const query &a, const query &b)
    { if (a.l / sq == b.l / sq) 
        return a.r < b.r;
    else
        return a.l < b.l; };
    sort(all(Qu), cmp);

    int lx = 0, rx = 0;
    fill(freq, freq + *max_element(A, A + N) + 1, 0);
    fill(cnt, cnt + N + 3, 0);
    for (query q : Qu)
    {
        while (rx < q.r)
            add(A[rx++]);
        while (lx > q.l)
            add(A[--lx]);
        while (rx > q.r)
            sub(A[--rx]);
        while (lx < q.l)
            sub(A[lx++]);

        n = q.r - q.l;
        pref = 0, suff = 0;
        tmp = 0;

        for (int i = 0; i < idx;)
        {
            if (cnt[stuff[i]] <= 0)
                swap(stuff[i], stuff[--idx]);
            else
                cnt[stuff[i]] *= -1, ++i;
        }
        sort(stuff, stuff + idx);

        for (int i = 0; i < idx; ++i)
        {
            ll x = stuff[i];
            cnt[x] *= -1;
            doStuff(x, (cnt[x] + 1) / 2);
            if (cnt[x] > 1)
            {
                doStuff(x, cnt[x] / 2);
                if (cnt[x] & 1)
                    swap(pref, suff);
            }
        }

        ans[q.idx] = tmp;
    }
    for (int i = 0; i < Q; ++i)
        cout << ans[i] << "\n";

    return 0;
}

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