Submission #573006

#	Time	Username	Problem	Language	Result	Execution time	Memory
573006		AmirElarbi	Event Hopping (BOI22_events)	C++14	10 / 100	176 ms	4428 KiB

events

#include <bits/stdc++.h>
#define vi vector<int>
#define ve vector
#define ll long long
#define vf vector<float>
#define vll vector<pair<ll,ll>>
#define ii pair<int,int>
#define vvi vector<vi>
#define vii vector<ii>
#define gii greater<ii>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define INF 1e9
#define eps 1e-7
#define eps1 1e-2
#define optimise ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define MAX_A 2e5+5
using namespace std;
const int MOD = 1e4+7;
const int nax = 1005;
const int nax2 = 200005;
typedef complex<int> Point;
#define X real()
#define Y imag()
int s[nax],e[nax];
vi adj[nax];
vi d;
int main(){
    optimise;
    int n,q;
    cin >> n >> q;
    for (int i = 0; i < n; ++i)
    {
        cin >> s[i] >> e[i];
    }
    for (int i = 0; i < n; ++i)
    {
        for (int j = 0; j < n; ++j)
        {
            if(i==j) continue;
            if(e[i] <= e[j] && s[j] <= e[i]) adj[i].pb(j);
        }
    }
    while(q--){
        int s,e;
        cin >> s >> e;
        s--,e--;
        int res = -1;
        if(s == e)
        {
            cout << 0 << endl;
            continue;
        }
        d.assign(n, INF);
        d[s] = 0;
        set<ii> q;
        q.insert({0, s});
        while (!q.empty()) {
            int v = q.begin()->second;
            q.erase(q.begin());
            for (auto edge : adj[v]) {
                int u = edge;
                if (d[v] + 1 < d[u]) {
                    q.erase({d[u], u});
                    d[u] = d[v] + 1;
                    if(u == e) {
                        res = d[u];
                        break;
                    }
                    q.insert({d[u], u});
                }
            }
        }
        if(res == -1) cout << "impossible" << endl;
        else cout << res << endl;
    }
}

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