Submission #1057066

#	Time	Username	Problem	Language	Result	Execution time	Memory
1057066		fv3	Shortcut (IOI16_shortcut)	C++14	0 / 100	2052 ms	440 KiB

shortcut

#include "shortcut.h"

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

vector<vector<pair<int, ll>>> adj;
int N;

vector<int> visited;
vector<ll> dist;

ll find_diameter()
{
    ll longest = 0;
    for (int i = N / 2; i < N; i++)
    {
        visited = vector<int>(N);
        dist = vector<ll>(N, 1ll << 60);

        priority_queue<pair<ll, int>> q;
        q.push({0, i});
        dist[i] = 0;

        int cnt = 0;
        while (1)
        {
            int s = q.top().second;
            q.pop(); 
            if (visited[s]) continue;
            visited[s] = 1; cnt++;

            for (auto node : adj[s])
            {
                if (visited[node.first] || dist[s] + node.second > dist[node.first]) continue;
                dist[node.first] = dist[s] + node.second;
                q.push({-dist[node.first], node.first});
            }

            if (cnt == N)
            {
                longest = max(longest, dist[s]);
                break;
            }
        }
    }
    
    return longest;
}

ll find_shortcut(int n, std::vector<int> l, std::vector<int> d, int c)
{
    N = 2 * n;
    adj.resize(N);

    for (int i = 0; i < n - 1; i++)
    {
        adj[i].push_back({i+1, l[i]});
        adj[i+1].push_back({i, l[i]});
    }

    for (int i = 0; i < n; i++)
    {
        adj[i].push_back({i+n, d[i]});
        adj[i+n].push_back({i, d[i]});
    }

    ll res = 1ll << 60;
    for (int i = 0; i < n - 1; i++)
    {
        for (int j = i+1; j < n; j++)
        {
            adj[i].push_back({j, c});
            adj[j].push_back({i, c});

            res = min(res, find_diameter());

            adj[i].pop_back();
            adj[j].pop_back();
        }
    }

    return res;
}

• 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