Submission #1086650

#	Time	Username	Problem	Language	Result	Execution time	Memory
1086650		SuPythony	Event Hopping (BOI22_events)	C++17	10 / 100	1595 ms	31048 KiB

events

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

vector<vector<int>> al;

int main() {
    int n,q; cin>>n>>q;
    vector<pair<int,int>> ev;
    for (int i=0; i<n; i++) {
        int s,e; cin>>s>>e;
        ev.push_back({s,e});
    }
    al.assign(n+1,vector<int>());
    for (int i=0; i<n; i++) {
        for (int j=0; j<n; j++) {
            if (i==j) continue;
            if (ev[j].first<=ev[i].second&&ev[i].second<=ev[j].second) {
                al[i+1].push_back(j+1);
            }
        }
    }
    while (q--) {
        int s,e; cin>>s>>e;
        queue<pair<int,int>> q;
        q.push({s,0});
        vector<int> vis(n+1,0);
        vis[s]=1;
        int ans=-1;
        if (s==e) ans=0;
        while (!q.empty()) {
            auto t=q.front(); q.pop();
            bool f=false;
            for (int v: al[t.first]) {
                if (v==e) {
                    ans=t.second+1;
                    f=true;
                    break;
                } else {
                    if (!vis[v]) {
                        vis[v]=1;
                        q.push({v,t.second+1});
                    }
                }
            }
            if (f) break;
        }
        if (ans==-1) cout<<"impossible\n";
        else cout<<ans<<"\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