제출 #579649

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
579649		Elias	Event Hopping (BOI22_events)	C++17	0 / 100	1588 ms	21792 KiB

events

#include <bits/stdc++.h>

#ifndef _DEBUG
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#endif

using namespace std;

#define int int64_t

template <class T>
istream &operator>>(istream &in, vector<T> &v)
{
    for (T &x : v)
        in >> x;
    return in;
}

struct Range
{
    int s, e, i;

    bool operator<(Range other) const
    {
        return tuple<int, int, int>{e, s, i} < tuple<int, int, int>{other.e, other.s, other.i};
    }
};

int n, q;

vector<Range> ranges, sR;

signed main()
{
    cin.tie(0);
    ios_base::sync_with_stdio(false);

    cin >> n >> q;

    ranges = vector<Range>(n);

    for (int i = 0; i < n; i++)
    {
        cin >> ranges[i].s >> ranges[i].e;
        ranges[i].i = i;
    }

    sR = ranges;

    sort(sR.begin(), sR.end());

    vector<vector<int>> next(20, vector<int>(n, -1));

    set<Range> reachable;

    for (int j = n - 2; j >= 0; j--)
    {
        auto [s, e, i] = sR[j];

        while (reachable.size() && prev(reachable.end())->s > e)
            reachable.erase(prev(reachable.end()));

        if (reachable.size())
            next[0][j] = prev(reachable.end())->i;

        reachable.insert({s, e, i});
    }

    for (int k = 1; k < 20; k++)
        for (int i = 0; i < n; i++)
        {
            int a = next[k - 1][i];
            if (a != -1)
                next[k][i] = next[k - 1][a];
        }

    while (q--)
    {
        int s, e;
        cin >> s >> e;

        s--, e--;

        if (s == e)
        {
            cout << "0\n";
            continue;
        }

        int count = 0;

        for (int k = 19; k >= 0; k--)
        {
            if (next[k][s] != -1 && ranges[next[k][s]].e < ranges[e].s)
            {
                s = next[k][s];
                count += pow(2, k);
            }
        }

        while (s != -1 && ranges[s].e < ranges[e].s)
        {
            s = next[0][s];
            count++;
        }

        if (s == -1 || ranges[s].e > ranges[e].e)
        {
            cout << "impossible\n";
        }
        else
        {
            cout << count + 1 << "\n";
        }
    }
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30