Submission #849862

#	Time	Username	Problem	Language	Result	Execution time	Memory
849862		Ahmed57	Event Hopping (BOI22_events)	C++17	10 / 100	1580 ms	35408 KiB

events

#include <bits/stdc++.h>
using namespace std;
vector<int> adj[100001];
signed main(){
    int n,q;
    cin>>n>>q;
    vector<pair<int,int>> v;
    for(int i = 0;i<n;i++){
        int a,b;cin>>a>>b;
        v.push_back({a,b});
    }
    for(int i = 0;i<n;i++){
        for(int j = 0;j<n;j++){
            if(i!=j){
                if(v[j].first<=v[i].second&&v[i].second<=v[j].second){
                    adj[i].push_back(j);
                }
            }
        }
    }
    vector<pair<int,int>> qu[n];
    for(int i = 0;i<q;i++){
        int a,b;cin>>a>>b;
        a--;b--;
        qu[a].push_back({b,i});
    }
    int ans[q] = {0};
    int cost[n] = {0};
    for(int i = 0;i<n;i++){
        for(int j = 0;j<n;j++){
            cost[j] = 1e9;;
        }
        queue<int> q;q.push(i);
        cost[i] = 0;
        while(!q.empty()){
            int x = q.front();q.pop();
            for(auto j:adj[x]){
                if(cost[j]==1e9){
                    cost[j] = cost[x]+1;
                    q.push(j);
                }
            }
        }
        for(auto j:qu[i]){
            ans[j.second] = cost[j.first];
        }
    }
    for(int i = 0;i<q;i++){
        if(ans[i]==1e9)cout<<"impossible\n";
        else cout<<ans[i]<<"\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