Submission #877538

#	Time	Username	Problem	Language	Result	Execution time	Memory
877538		vjudge1	Event Hopping (BOI22_events)	C++17	10 / 100	1564 ms	31016 KiB

events

#include <bits/stdc++.h>

#define pb push_back
#define eb emplace_back
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define uniq(x) x.erase(unique(all(x)), x.end())
#define rall(x) x.rbegin(), x.rend()
//#define int long long

using namespace std;

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

const int mod = 1e9 + 7;
const int LOG = 20;
const int maxn = 1e5 + 5;
const double eps = 1e-9;

void setIO() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
}

int32_t main() {
    setIO();

    int n, q;
    cin >> n >> q;
    vector<pii> v(n+1);

    for(int i=1; i<=n; i++) cin >> v[i].first >> v[i].second;

    vector<vector<int> > graph(n+1);
    for(int i=1; i<=n; i++) {
        for(int j=1; j<=n; j++) {
            if(i == j) continue;
            if(v[j].first <= v[i].second && v[i].second <= v[j].second)
                graph[i].push_back(j);
        }
    }

    auto bfs = [&](int a, int b) {
        vector<bool> vis(n+1);
        vector<int> dist(n+1, 0);
        queue<int> q;
        vis[a] = 1;
        q.push(a);

        while(!q.empty()) {
            int u = q.front();
            q.pop();

            if(u == b) return dist[b];

            for(int &v : graph[u]) {
                if(vis[v]) continue;
                dist[v] = dist[u] + 1;
                vis[v] = 1;
                q.push(v);
            }
        }

        return -1;
    };

    while(q--) {
        int a, b;
        cin >> a >> b;
        
        int ans = bfs(a, b);
        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