Submission #1120931

#	Time	Username	Problem	Language	Result	Execution time	Memory
1120931		vjudge1	Event Hopping (BOI22_events)	C++17	0 / 100	1539 ms	4100 KiB

events

#include <bits/stdc++.h>

#define ll long long
#define all(x) x.begin(), x.end()
#define in insert
#define F first
#define S second
#define ppf pop_front
#define pb push_back
#define ppb pop_back
#define pf push_front
#define pii pair <int, int>
#define pll pair <ll, ll>
#define boost() ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define sz(x) (int)x.size()

using namespace std;

const int N = 1e5+123;
const ll mod = 1e9+7;

vector<int> g[N];

void solve() {
    int n,q;
    cin >> n >> q;
    pii a[n+1];
    for(int i=1 ; i <= n ; i++){
        cin >> a[i].F >> a[i].S;
    }
    
    sort(a+1 , a+1+n);
    for(int i=1; i <= n ; i++){
        for(int j=1 ; j <= n ; j++){
            if(i == j)
                continue;
            if(a[j].F <= a[i].S && a[i].S <= a[j].S){
                g[i].pb(j);
            }
        }
    }
    
    while(q--){
        int x,y;
        cin >> x >> y;
        vector<int> dis(n+1 , -1);
        queue<int> qu;
        dis[x]=0;
        qu.push(x);
        
        while(!qu.empty()){
            int v=qu.front();
            qu.pop();
            
            for(int to : g[v]){
                if(dis[to] == -1){
                    dis[to]=dis[v]+1;
                    qu.push(to);
                }
            }
        }
        if(dis[y] == -1){
            cout << "impossible\n";
        }
        else
            cout << dis[y] << endl;
    }
}

signed main() {
    boost();
    int tt=1;
    //cin >> tt;
    while (tt--) {
        solve();
    }
    return 0;
}

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