Submission #599069

#	Time	Username	Problem	Language	Result	Execution time	Memory
599069		SlavicG	Event Hopping (BOI22_events)	C++17	10 / 100	1596 ms	107588 KiB

events

#include "bits/stdc++.h"
using namespace std;

const int N = 5000;
int dist[N][N];
int l[N], r[N];
void go(set<pair<int, int>> s, int start) {
    queue<int> q;
    q.push(start);
    dist[start][start] = 0;
    s.erase({r[start], start});
    while(!q.empty()) {
        int u = q.front();
        q.pop();
        while(!s.empty()) {
            auto it = s.upper_bound({l[u], -1});
            if(it == s.end()) break;
            if(it->first > r[u]) break;
            dist[start][it->second] = dist[start][u] + 1;
            q.push(it->second);
            s.erase(it);
        }
    }
}
int main() {
    int n, q; cin >> n >> q;
    for(int i = 0; i < n; ++i) cin >> l[i] >> r[i];
    set<pair<int, int>> s;
    for(int i = 0; i < n; ++i) s.insert({r[i], i});
    for(int i = 0; i < N; ++i) for(int j = 0; j < N; ++j) dist[i][j] = -1;
    for(int i = 0; i < n; ++i) go(s, i);
    while(q--) {
        int a, b; cin >> a >> b; --a, --b;
        if(dist[b][a] == -1) cout << "impossible\n";
        else cout << dist[b][a] << "\n";
    }
}

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