Submission #1172057

#	Time	Username	Problem	Language	Result	Execution time	Memory
1172057		yoav_s	Event Hopping (BOI22_events)	C++20	10 / 100	1595 ms	1864 KiB

events

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef vector<ll> v;
typedef vector<v> vv;
typedef vector<vv> vvv;
typedef pair<ll, ll> p;
typedef vector<p> vp;
typedef vector<vp> vvp;
typedef vector<vvp> vvvp;
typedef pair<ll, p> tri;
typedef vector<tri> vtri;
typedef vector<vtri> vvtri;
typedef vector<vvtri> vvvtri;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<vvb> vvvb;

#define f first
#define s second
#define pb push_back
#define eb emplace_back
#define all(v) (v).begin(),(v).end()

const ll INF = 1e18;
const ll mod = 1e9 + 7;

int main()
{
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
    ll N, Q;
    cin >> N >> Q;
    vp events(N);
    for (ll i = 0; i < N; i++) cin >> events[i].f >> events[i].s;
    while (Q--)
    {
        ll s, e;
        cin >> s >> e; s--; e--;
        if (s == e)
        {
            cout << "0\n";
            continue;
        }
        if (events[s].s > events[e].s)
        {
            cout << "impossible\n";
            continue;
        }
        ll curEvent = e;
        ll hops = 0;
        bool poss = true;
        while (true)
        {
            ll earliestStart = events[curEvent].f;
            ll bestEvent = curEvent;
            if (events[s].s >= events[curEvent].f)
            {
                hops++;
                break;
            }
            for (ll i = 0; i < N; i++)
            {
                if (events[i].s >= events[curEvent].f && events[i].s <= events[curEvent].s)
                {
                    if (events[i].f < earliestStart)
                    {
                        earliestStart = events[i].f;
                        bestEvent = i;
                    }
                }
            }
            if (bestEvent == curEvent)
            {
                poss = false;
                break;
            }
            hops++;
            curEvent = bestEvent;
        }
        if (poss) cout << hops << "\n";
        else cout << "impossible\n";
    }
    return 0;
}

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