Submission #1195952

#	Time	Username	Problem	Language	Result	Execution time	Memory
1195952		quangminh412	Construction Project 2 (JOI24_ho_t2)	C++20	100 / 100	128 ms	23340 KiB

Main

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

/*
  Ben Watson
  Handle codeforces : quangminh98

  Mua Code nhu mua Florentino !!
*/

#define ll long long

const string name = "test";

void solve();
signed main()
{
    if (fopen((name + ".inp").c_str(), "r"))
    {
        freopen((name + ".inp").c_str(), "r", stdin);
        freopen((name + ".out").c_str(), "w", stdout);
    }
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    solve();

    return 0;
}

// main program
const int maxn = 2e5 + 1;
const ll oo = 0x3f3f3f3f3f3f3f3f;

vector<pair<int, int>> adj[maxn];
int n, m, s, t, l;
ll k;

vector<ll> Dijkstra(int source)
{
    vector<ll> dist(n + 1, oo);
    priority_queue<pair<ll, int>, vector<pair<ll, int>>, greater<pair<ll, int>>> pq;
    pq.push({dist[source] = 0, source});
    while (!pq.empty())
    {
        int u = pq.top().second;
        ll w = pq.top().first;
        pq.pop();

        if (dist[u] != w)
            continue;

        for (pair<int, int> nxt : adj[u])
        {
            int v = nxt.first, w = nxt.second;

            if (dist[v] > dist[u] + w)
                pq.push({dist[v] = dist[u] + w, v});
        }
    }

    return dist;
}

void solve()
{
    cin >> n >> m >> s >> t >> l >> k;
    for (int i = 0; i < m; i++)
    {
        int u, v, c;
        cin >> u >> v >> c;

        adj[u].push_back({v, c});
        adj[v].push_back({u, c});
    }

    vector<ll> S = Dijkstra(s), T = Dijkstra(t);
    if (S[t] <= k)
    {
        cout << 1ll * n * (n - 1) / 2 << '\n';
        return;
    }

    sort(S.begin() + 1, S.end());
    sort(T.begin() + 1, T.end());
    ll res = 0;
    for (int i = 1; i <= n; i++)
    {
        int pos = upper_bound(T.begin() + 1, T.end(), k - l - S[i]) - T.begin();
        res +=  pos - 1;
    }

    cout << res << '\n';
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:20:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |         freopen((name + ".inp").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:21:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |         freopen((name + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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