Submission #674497

#	Time	Username	Problem	Language	Result	Execution time	Memory
674497		stanislavpolyn	Event Hopping (BOI22_events)	C++17	25 / 100	1589 ms	2532 KiB

events

#include <bits/stdc++.h>

#define fr(i, a, b) for (int i = (a); i <= (b); i++)
#define rf(i, a, b) for (int i = (a); i >= (b); i--)
#define fe(x, y) for (auto& x : y)

#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define mt make_tuple

#define pw(x) (1LL << (x))
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()

using namespace std;

mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());

#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template <typename T>
using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define fbo find_by_order
#define ook order_of_key

template <typename T>
bool umn(T& a, T b) {
    return a > b ? a = b, 1 : 0;
}
template <typename T>
bool umx(T& a, T b) {
    return a < b ? a = b, 1 : 0;
}

using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
template <typename T>
using ve = vector<T>;

const int N = 1e5 + 5;

int n, q;
ve<pii> a;
int to[N];

int go[N][20];

int main() {
#ifndef LOCAL
    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);
    ios::sync_with_stdio(0);
    cin.tie(0);
#else
    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);
#endif

    cin >> n >> q;
    a.resize(n + 1);
    fr (i, 1, n) {
        cin >> a[i].fi >> a[i].se;
        // to[i] = i;
    }

    fr (i, 1, n) {
        fr (j, 1, n) {
            if (i == j) continue;

            if (a[j].se >= a[i].fi && a[j].se <= a[i].se) {
                if (!to[i] || a[to[i]].fi > a[j].fi) {
                    to[i] = j;
                }
            }
        }
    }

    fr (i, 1, n) {
        go[i][0] = to[i];
    }

    fr (p, 1, 19) {
        fr (i, 1, n) {
            go[i][p] = go[go[i][p - 1]][p - 1];
        }
    }

    fr (i, 0, q - 1) {
        int s, e;
        cin >> s >> e;

        if (a[s].se > a[e].se) {
            cout << "impossible\n";
            continue;
        }
        if (s == e) {
            cout << "0\n";
            continue;
        }

        int v = e;
        int ans = 0;
        rf (p, 19, 0) {
            if (go[v][p] && a[go[v][p]].fi > a[s].se) {
                ans += pw(p);
                v = go[v][p];
            }
        }

        if (to[v] && a[v].fi > a[s].se) {
            v = to[v];
            ans++;
        }

        if (a[v].fi <= a[s].se) {
            ans++;
            cout << ans << "\n";
        } else {
            cout << "impossible\n";
        }
    }

    return 0;
}

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