Submission #1274939

#	Time	Username	Problem	Language	Result	Execution time	Memory
1274939		hynmj	Construction Project 2 (JOI24_ho_t2)	C++20	8 / 100	259 ms	25780 KiB

Main

#include <bits/stdc++.h>
#define pi pair<int, int>
#define int long long
#define ff first
#define ss second
using namespace std;
const int N = 1ll << 18;
vector<pi> graph[N];
int value[N << 3];

void add(int i, int val, int cur = 1, int l = 0, int r = N)
{
    if (i < l || i > r)
        return;
    if (l == r)
    {
        value[cur] += val;
        return;
    }
    int lc = cur + cur, rc = lc + 1, mid = (l + r) / 2;
    add(i, val, lc, l, mid);
    add(i, val, rc, mid + 1, r);
    value[cur] = value[lc] + value[rc];
}

int calculate(int l, int r, int cur = 1, int st = 0, int en = N)
{
    if (r < st || l > en)
        return 0;
    if (st >= l && en <= r)
        return value[cur];
    int lc = cur + cur, rc = lc + 1, mid = (st + en) / 2;
    return calculate(l, r, lc, st, mid) + calculate(l, r, rc, mid + 1, en);
}

vector<int> dijkstra(int start)
{
    vector<int> dist(N, 1e18);
    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;
                q.push({dist[i.ss], i.ss});
            }
        }
    }
    return dist;
}

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 = dijkstra(s);
    vector<int> tdist = dijkstra(t);
    if (sdist[t] <= k)
    {
        cout << n * (n - 1) / 2;
        return;
    }
    int ans1 = 0;
    int ans = 0;
    // add(0, 1);
    for (int i = 1; i <= n; i++)
    {
        if (tdist[i] <= 1e18)
            add(tdist[i], 1);
        // cout << calculate(0, 1) << endl;
    }

    for (int i = 1; i <= n; i++)
    {
        // continue;
        if (tdist[i] <= n)
            add(tdist[i], -1);
        int kk = calculate(0, k - l - sdist[i]);
        ans += kk;
        // cout << "for " << i << " we have " << kk << endl;
        // cout << "ans  = " << ans << endl;
    }

    for (int i = 1; i <= n; i++)
    {
        if (sdist[i] <= 1e18)
            add(sdist[i], 1);
        // cout << calculate(0, 1) << endl;
    }

    for (int i = 1; i <= n; i++)
    {
        // continue;
        if (sdist[i] <= n)
            add(sdist[i], -1);
        int kk = calculate(0, k - l - tdist[i]);
        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: 0 / 16
• Subtask 3: 0 / 29
• Subtask 4: 0 / 47