Submission #871652

#	Time	Username	Problem	Language	Result	Execution time	Memory
871652		sleepntsheep	Untitled (POI11_rot)	C++17	90 / 100	604 ms	65536 KiB

Main

#include <iostream>
#include <cstring>
#include <vector>
#include <algorithm>
#include <deque>
#include <set>
#include <utility>
#include <array>

using i64 = long long;
using u64 = unsigned long long;
using f64 = double;
using f80 = long double;

using namespace std;
#define ALL(x) x.begin(), x.end()
#define ShinLena cin.tie(nullptr)->sync_with_stdio(false);
#define N 1000005

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;
using oset = tree<pair<int, int>, null_type, less<pair<int, int>>, rb_tree_tag, tree_order_statistics_node_update>;

int root, n, A[N], L[N], R[N], alloc;
oset *a[N];
i64 t[N], sz[N];

int read()
{
    int u = ++alloc, p;
    cin >> p;
    if (p) return sz[u] = 1, (a[u] = new oset())->insert({A[u] = p, u}), u;
    L[u] = read(); R[u] = read();
    return sz[u] = sz[L[u]] + sz[R[u]], u;
}

static inline i64 qry(u64 p)
{
    u64 z{0};
    for (; p < N; p+=p&-p) z += t[p];
    return z;
}

static inline void upd(u64 p, i64 k)
{
    for (; p; p-=p&-p) t[p] += k;
}


u64 order(const oset &s, oset::iterator it)
{
    return it == s.end() ? s.size() : s.order_of_key(*it);
}

void dfs0(int u)
{
    if (!L[u]) return;

    dfs0(L[u]), dfs0(R[u]);

    u64 l2r = 0, r2l = 0;

    if (a[R[u]]->size() > a[L[u]]->size())
    {
        for (const pair<int, int> &x : *a[L[u]])
            l2r += order(*a[R[u]], a[R[u]]->lower_bound({x.first, 0})),
            r2l += sz[R[u]] - order(*a[R[u]], a[R[u]]->lower_bound({x.first+1, 0}));
    }
    else
    {
        for (const pair<int, int> &x : *a[R[u]])
            l2r += sz[L[u]] - order(*a[L[u]], a[L[u]]->lower_bound({x.first+1, 0})),
            r2l += order(*a[L[u]], a[L[u]]->lower_bound({x.first, 0}));
    }

    if (r2l < l2r) swap(L[u], R[u]);

    if (sz[R[u]] > sz[L[u]])
    {
        a[u] = a[R[u]];
        for (auto x : *a[L[u]]) a[u]->insert(x);
        delete a[L[u]];
    }
    else
    {
        a[u] = a[L[u]];
        for (auto x : *a[R[u]]) a[u]->insert(x);
        delete a[R[u]];
    }
}


vector<int> corona;

void dfs2(int u)
{
    if (!L[u]) corona.push_back(A[u]);
    else dfs2(L[u]), dfs2(R[u]);
}

int main()
{
    ShinLena;
    cin >> n;
    root = read();

    dfs0(root);
    delete a[root];
    dfs2(root);

    u64 z{0};

    for (auto x : corona) upd(x, 1), z += qry(x+1);

    cout << z;
    return 0;
}

• Subtask 1: 9 / 9
• Subtask 2: 9 / 9
• Subtask 3: 9 / 9
• Subtask 4: 9 / 9
• Subtask 5: 9 / 9
• Subtask 6: 9 / 9
• Subtask 7: 9 / 9
• Subtask 8: 9 / 9
• Subtask 9: 9 / 9
• Subtask 10: 9 / 9
• Subtask 11: 0 / 10