Submission #1010278

#	Time	Username	Problem	Language	Result	Execution time	Memory
1010278		overwatch9	Shortcut (IOI16_shortcut)	C++17	0 / 100	2093 ms	348 KiB

shortcut

#include "shortcut.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
vector <vector <pair <int, int>>> adj;
int N;
pair <int, ll> dijkstra(int s) {
    priority_queue <pair <ll, int>> pq;
    vector <ll> dis(N+1, 1e17);
    vector <bool> processed(N+1);
    dis[s] = 0;
    pq.push({0, s});
    int node = 0;
    ll mx = 0;
    while (!pq.empty()) {
        s = pq.top().second;
        pq.pop();
        if (processed[s])
            continue;
        processed[s] = true;
        if (mx < dis[s]) {
            mx = dis[s];
            node = s;
        }
        for (auto i : adj[s]) {
            if (dis[i.first] > dis[s] + i.second) {
                dis[i.first] = dis[s] + i.second;
                pq.push({-dis[i.first], i.first});
            }
        }
    }
    return {node, mx};
}
ll find_shortcut(int n, vector<int> l, vector<int> d, int c)
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    adj.resize(n * 2 + 5);
    for (int i = 0; i+1 < n; i++) {
        adj[i].push_back({i+1, l[i]});
        adj[i+1].push_back({i, l[i]});
    }
    int ogn = n;
    for (int i = 0; i < ogn; i++) {
        if (d[i] == 0)
            continue;
        adj[i].push_back({n, d[i]});
        adj[n].push_back({i, d[i]});
        n++;
    }
    N = n;
    pair <int, ll> res;
    ll ans = 0;
    for (int i = 0; i < n; i++) {
        res = dijkstra(i);
        res = dijkstra(res.first);
        ans = max(ans, res.second);
    }
    for (int i = 0; i < ogn; i++) {
        for (int j = i+1; j < ogn; j++) {
            adj[i].push_back({j, c});
            adj[j].push_back({i, c});
            ll tp = 0;
            for (int k = 0; k < n; k++) {
                res = dijkstra(k);
                res = dijkstra(res.first);
                tp = max(tp, res.second);
            }
            ans = min(ans, tp);
            adj[i].pop_back();
            adj[j].pop_back();
        }
    }
    return ans;
}
// int main() {
//     int n;
//     cin >> n;
//     vector <int> l(n), d(n);
//     for (int i = 0; i < n-1; i++)
//         cin >> l[i];
//     for (int i = 0; i < n; i++)
//         cin >> d[i];
//     int c;
//     cin >> c;
//     cout << find_shortcut(n, l, d, c) << '\n';
// }

• Subtask 1: 0 / 9
• Subtask 2: 0 / 14
• Subtask 3: 0 / 8
• Subtask 4: 0 / 7
• Subtask 5: 0 / 33
• Subtask 6: 0 / 22
• Subtask 7: 0 / 4
• Subtask 8: 0 / 3