Submission #1015226

#	Time	Username	Problem	Language	Result	Execution time	Memory
1015226		aufan	Passport (JOI23_passport)	C++17	100 / 100	290 ms	73084 KiB

passport

#include <bits/stdc++.h>
#define int long long
#define fi first
#define se second

using namespace std;

const int INFF = 1e18;

int32_t main()
{
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
        
        int n;
        cin >> n;

        vector<int> l(n), r(n);
        for (int i = 0; i < n; i++) cin >> l[i] >> r[i];

        // build somewhat iterative segtree-like segments (?)
        int sz = 1;
        while (sz < n) {
                sz *= 2;
        }

        vector<vector<int>> v(2 * sz);
        for (int i = 0; i < n; i++) {
                int cl = l[i] + sz - 1;
                int cr = r[i] + sz;

                while (cl < cr) {
                        if (cl & 1) {
                                v[cl++].push_back(i);
                        }

                        if (cr & 1) {
                                v[--cr].push_back(i);
                        }

                        cl >>= 1;
                        cr >>= 1;
                }
        }

        auto bfs = [&](int x) { 
                vector<int> dist(n, INFF), q(1, x), vis(n), used(2 * sz);
                dist[x] = 0;
                for (int i = 0; i < (int)q.size(); i++) {
                        int x = q[i];

                        if (!vis[x]) {
                                vis[x] = 1;
                                int id = x + sz;
                                while (id >= 1 && !used[id]) {
                                        used[id] = 1;
                                        for (auto z : v[id]) {
                                                if (dist[z] == INFF) {
                                                        dist[z] = dist[x] + 1;
                                                        q.push_back(z);
                                                }
                                        }

                                        id >>= 1;
                                }
                        }
                }

                return dist;
        };

        vector<int> df = bfs(0), db = bfs(n - 1), dc(n, INFF);
        priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
        df[0] = db[n - 1] = 1;
        for (int i = 0; i < n; i++) {
                dc[i] = min(dc[i], df[i] + db[i]);
                pq.push({dc[i], i});
        }

        vector<int> vis(n), used(2 * sz);
        while (!pq.empty()) {
                auto [w, x] = pq.top();
                pq.pop();

                if (!vis[x]) {
                        vis[x] = 1;
                        int id = x + sz;
                        while (id >= 1 && !used[id]) {
                                used[id] = 1;
                                for (auto z : v[id]) {
                                        if (dc[x] + 1 < dc[z]) {
                                                dc[z] = dc[x] + 1;
                                                pq.push({dc[z], z});
                                        }
                                }

                                id >>= 1;
                        }
                }
        }

        vector<int> ans(n);
        for (int i = 0; i < n; i++) {
                ans[i] = (dc[i] == INFF ? -1 : dc[i] - 1);
        }

        int q;
        cin >> q;

        for (int i = 0; i < q; i++) {
                int x;
                cin >> x;
                --x;

                cout << ans[x] << '\n';
        }
        
        return 0;
}

• Subtask 1: 6 / 6
• Subtask 2: 16 / 16
• Subtask 3: 24 / 24
• Subtask 4: 8 / 8
• Subtask 5: 46 / 46