Submission #1263102

#	Time	Username	Problem	Language	Result	Execution time	Memory
1263102		norman165	Construction Project 2 (JOI24_ho_t2)	C++20	53 / 100	2094 ms	57772 KiB

Main

#include <bits/stdc++.h>

#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define int long long
#define yes() cout << "YES\n"
#define no() cout << "NO\n"

using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;

const int inf = 1e18;
const int mod = 1e9 + 7;
const int maxn = 1e6;
const int mod1 = 998244353;
const int mod2 = 1e18 + 1;
const int mod3 = 1e9 + 9;
const int mod4 = 333333333;
const int mod5 = 200000;
const int mod6 = 10007;
const int k = 3000;
const int w = 1e5;
const ld EPS = 1e-8;

int LOG = 30;

struct segTree {
    vector<int> t;
    int n;

    segTree(int x) {
        n = x;
        t.resize(4 * n);
    }

    int get(int v, int l, int r, int ql, int qr) {
        if (l >= qr || r <= ql) return 0ll;
        if (ql <= l && r <= qr) return t[v];

        int m = (l + r) / 2;
        return get(2 * v, l, m, ql, qr) + get(2 * v + 1, m, r, ql, qr);
    }

    int get(int ql, int qr) {
        return get(1, 0, n, ql, qr);
    }

    void upd(int v, int l, int r, int idx, int val) {
        if (r - l == 1) {
            t[v] += val;
            return;
        }

        int m = (l + r) / 2;
        if (idx < m) upd(2 * v, l, m, idx, val);
        else upd(2 * v + 1, m, r, idx, val);

        t[v] = t[2 * v] + t[2 * v + 1];
    }

    void upd(int idx, int val) {
        upd(1, 0, n, idx, val);
    }
};

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

    vector<vector<pair<int, int>>> g(n);
    for (int i = 0; i < m; i++) {
        int u, v, w;
        cin >> u >> v >> w;

        u--, v--;
        g[u].push_back({v, w});
        g[v].push_back({u, w});
    }

    vector<int> d1(n, inf);
    set<pair<int, int>> st;
    d1[s] = 0;
    st.insert({0, s});

    while (st.size()) {
        int v = st.begin()->second;
        st.erase(st.begin());

        for (auto& [u, w] : g[v]) {
            if (d1[u] > d1[v] + w) d1[u] = d1[v] + w, st.insert({d1[u], u});
        }
    }

    if (d1[t] <= k) {
        cout << n * (n - 1) / 2 << "\n";
        return;
    }

    vector<int> d2(n, inf);
    d2[t] = 0;
    st.insert({0, t});

    while (st.size()) {
        int v = st.begin()->second;
        st.erase(st.begin());

        for (auto& [u, w] : g[v]) {
            if (d2[u] > d2[v] + w) d2[u] = d2[v] + w, st.insert({d2[u], u});
        }
    }

    segTree st1(3e5), st2(3e5);
    set<int> st3, st4;
    vector<int> c;
    for (int i = 0; i < n; i++) c.push_back(d2[i]);
    sort(all(c));
    c.resize(unique(all(c)) - c.begin());

    int ans = 0;
    // for (int i = 0; i < n; i++) {
    //     for (int j = i + 1; j < n; j++) {
    //         if (d1[i] + d2[j] + l <= k) ans++;
    //     }
    // }

    for (int i = n - 1; i >= 0; i--) {
        auto it = st3.upper_bound(k - l - d1[i]);
        if (it != st3.begin()) {
            it--;
            int idx = lower_bound(all(c), *it) - c.begin();
            ans += st1.get(0, idx + 1);
        }

        int idx = lower_bound(all(c), d2[i]) - c.begin();
        st1.upd(idx, 1);
        st3.insert(d2[i]);
    }

    // for (int i = n - 1; i >= 0; i--) {
    //     if (k - l - d1[i] >= 0) ans += st1.get(0, k - l - d1[i] + 1);
    //     st1.upd(d2[i], 1);
    // }
    //
    // for (int i = n - 1; i >= 0; i--) {
    //     if (k - l - d2[i] >= 0) ans += st2.get(0, k - l - d2[i] + 1);
    //     st2.upd(d1[i], 1);
    // }

    // for (int i = 0; i < n; i++) {
    //     for (int j = i + 1; j < n; j++) {
    //         if (d2[i] + d1[j] + l <= k) ans++;
    //     }
    // }
    c.clear();
    for (int i = 0; i < n; i++) c.push_back(d1[i]);
    sort(all(c));
    c.resize(unique(all(c)) - c.begin());
    for (int i = n - 1; i >= 0; i--) {
        auto it = st4.upper_bound(k - l - d2[i]);
        if (it != st4.begin()) {
            it--;
            int idx = lower_bound(all(c), *it) - c.begin();
            ans += st2.get(0, idx + 1);
        }

        int idx = lower_bound(all(c), d1[i]) - c.begin();
        st2.upd(idx, 1);
        st4.insert(d1[i]);
    }

    cout << ans << "\n";
}

signed main() {
    // cout.precision(16);

    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t = 1;
    // cin >> t;

    while (t--) {
        solve();
    }
}

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