Submission #1274987

#	Time	Username	Problem	Language	Result	Execution time	Memory
1274987		hynmj	Construction Project 2 (JOI24_ho_t2)	C++20	53 / 100	272 ms	29956 KiB

Main

#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#define pi pair<int, int>
#define int long long
#define ff first
#define ss second
const int N = 2e5 + 7;
using namespace std;
vector<pi> graph[N];
namespace __gnu_pbds
{
    typedef tree<int,
                 null_type,
                 less_equal<int>,
                 rb_tree_tag,
                 tree_order_statistics_node_update>
        ordered_set;
}
using namespace __gnu_pbds;

void Erase(ordered_set &s, int x)
{
    s.erase(s.upper_bound(x));
}

int FirstIdx(ordered_set &s, int x)
{
    return (s.order_of_key(x));
}

int Value(ordered_set &s, int idx)

{

    return (*s.find_by_order(idx));
}

void Clear(ordered_set &s)
{

    s.clear();
}

void dijkstra(int start, vector<int> &dist)
{
    vector<int> vis(dist.size(), 0);

    priority_queue<pi, vector<pi>, greater<pi>> q;
    q.push({0, start});
    dist[start] = 0;
    int node, weight;
    while (q.size())
    {
        node = q.top().ss;
        q.pop();
        for (auto i : graph[node])
        {
            if (dist[i.ss] > dist[node] + i.ff)
            {
                dist[i.ss] = dist[node] + i.ff;
                if (vis[i.ss] == 0)
                    q.push({dist[i.ss], i.ss});
                vis[i.ss] = 1;
            }
        }
    }
}

void solve()
{
    int n, m;
    cin >> n >> m;
    int s, t, l, k;
    cin >> s >> t >> l >> k;

    int u, v, w;

    for (int i = 0; i < m; i++)
    {
        cin >> u >> v >> w;
        graph[u].push_back({w, v});
        graph[v].push_back({w, u});
    }
    vector<int> sdist(n + 1, 1e18);
    dijkstra(s, sdist);
    vector<int> tdist(n + 1, 1e18);
    dijkstra(t, tdist);
    if (sdist[t] <= k)
    {
        cout << n * (n - 1) / 2;
        return;
    }
    int ans1 = 0;
    int ans = 0;

    // cout << ans1 << endl;
    // cout << "------" << endl;
    // update(0, 1);
    ordered_set st;
    for (int i = 1; i <= n; i++)
    {
        if (tdist[i] <= k - l)
            st.insert(tdist[i]);
        // cout << tdist[i] << " ";
    }
    // cout << endl;
    // for (int i = 1; i <= n; i++)
    // {
    // cout << sdist[i] << " ";
    // }
    // cout << endl;
    // cout << query(0, 2) << endl;

    for (int i = 1; i <= n; i++)
    {
        // continue;
        if (tdist[i] <= k - l)
            Erase(st, tdist[i]);
        int kk = FirstIdx(st, k - l - sdist[i] + 1);
        ans += kk;
        // cout << "for " << i << " we have " << kk << endl;
        // cout << "ans  = " << ans << endl;
    }
    Clear(st);

    for (int i = 1; i <= n; i++)
    {
        if (sdist[i] < 1e18)
            st.insert(sdist[i]);
        // cout << query(0, 1) << endl;
    }

    for (int i = 1; i <= n; i++)
    {
        // continue;
        if (sdist[i] < 1e18)
            Erase(st, sdist[i]);
        int kk = FirstIdx(st, k - l - tdist[i] + 1);

        ans += kk;
        // cout << "for " << i << " we have " << kk << endl;
        // cout << "ans  = " << ans << endl;
    }

    cout << ans << endl;
}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);
    int t = 1;
    // cin >> t;
    while (t--)
    {
        solve();
        cout << endl;
    }
    return 0;
}

• Subtask 1: 8 / 8
• Subtask 2: 16 / 16
• Subtask 3: 29 / 29
• Subtask 4: 0 / 47