Submission #799413

#	Time	Username	Problem	Language	Result	Execution time	Memory
799413		Johann	Diversity (CEOI21_diversity)	C++14	64 / 100	7029 ms	17112 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;
vi A;
vi ans;
vi freq;
ll tmp, pref, suff, n;

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

ll numberOfSubsequences(ll x)
{
    return x * (x + 1) / 2;
}
ll cach3[300010];
ll totalLengthOfSubsequences(ll x)
{
    if (cach3[x] == -1)
        cach3[x] = x * (x + 1) * (x + 1) / 2 - (2 * x + 1) * (x + 1) * x / 6;
    return cach3[x];
}
void doStuff(ll x, ll y)
{
    ll len = x * y;

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

    pref += len;
    swap(pref, suff);
}
struct segtree
{
    vi arr;
    int size;
    void init(int _size)
    {
        size = 1;
        while (size < _size)
            size *= 2;
        arr.assign(2 * size, 0);
    }
    void add(int i, int v)
    {
        i += size;
        while (i > 0)
        {
            arr[i] += v;
            i /= 2;
        }
    }
    void dfs(int x)
    {
        if (arr[x] == 0)
            return;
        if (x < size)
        {
            dfs(2 * x);
            dfs(2 * x + 1);
        }
        else
        {
            // arr[x] := how often
            if (arr[x] & 1)
                doStuff(x - size, 1);
            if (arr[x] > 1)
            {
                doStuff(x - size, arr[x] / 2);
                doStuff(x - size, arr[x] / 2);
            }
        }
    }
};
segtree seg;
void add(int x)
{
    if (freq[x] > 0)
        seg.add(freq[x], -1);
    ++freq[x];
    seg.add(freq[x], 1);
}
void sub(int x)
{
    seg.add(freq[x], -1);
    --freq[x];
    if (freq[x])
        seg.add(freq[x], 1);
}

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

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

    vector<query> Qu(Q);
    ans.resize(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);

    fill(cach3, cach3 + N + 2, -1);

    int lx = 0, rx = 0;
    freq.assign(*max_element(all(A)) + 1, 0);
    seg.init(N + 1);
    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 = totalLengthOfSubsequences(n);

        seg.dfs(1);

        ans[q.idx] = tmp;
    }
    for (ll x : ans)
        cout << x << "\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: 0 / 36