Submission #1319058

#	Time	Username	Problem	Language	Result	Execution time	Memory
1319058		Bolatulu	Construction Project 2 (JOI24_ho_t2)	C++20	100 / 100	239 ms	30204 KiB

Main

#include <bits/stdc++.h>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef long double db;

#define int ll
#define all(x) (x).begin(), (x).end()
#define md ((tl + tr) >> 1)
#define TL v + v, tl, md
#define TR v + v + 1, md + 1, tr
#define Tl t[v].l, tl, md
#define Tr t[v].r, md + 1, tr

constexpr int maxn = 1'000'007;
constexpr ll inf = 1e18 + 7;
constexpr ll M = 998244353;

int binpow(int a, int n) {
    if (n == 0)
        return 1;
    if (n & 1)
        return a * binpow(a, n - 1) % M;
    int x = binpow(a, n >> 1);
    return x * x % M;
}

const int dx[4] = {-1, 0, 1, 0};
const int dy[4] = {0, 1, 0, -1};
const db eps = 0.000000000000001;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

int random(int l, int r) {
    return uniform_int_distribution<int>(l, r)(rng);
}

int n, m, s, t, l, k, ds[maxn], dt[maxn];
vector<pair<int, int>> g[maxn];

void solve() {
    cin >> n >> m >> s >> t >> l >> k;
    for (int i = 1; i <= m; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        g[a].emplace_back(b, c);
        g[b].emplace_back(a, c);
    }

    for (int i = 1; i <= n; i++) {
        ds[i] = dt[i] = inf;
    }
    set<pair<int, int>> q;
    ds[s] = 0;
    q.insert({0, s});
    while (!q.empty()) {
        int v = q.begin()->second;
        q.erase(q.begin());
        for (auto [to, len] : g[v]) {
            if (ds[v] + len < ds[to]) {
                q.erase({ds[to], to});
                ds[to] = ds[v] + len;
                q.insert({ds[to], to});
            }
        }
    } 
    
    q.clear();
    dt[t] = 0;
    q.insert({0, t});
    while (!q.empty()) {
        int v = q.begin()->second;
        q.erase(q.begin());
        for (auto [to, len] : g[v]) {
            if (dt[v] + len < dt[to]) {
                q.erase({dt[to], to});
                dt[to] = dt[v] + len;
                q.insert({dt[to], to});
            }
        }
    } 

    if (ds[t] <= k) {
        cout << n * (n - 1) / 2;
        return;
    }
    vector<int> vs, vt;
    for (int i = 1; i <= n; i++) {
        vs.push_back(ds[i]);
        vt.push_back(dt[i]);
    }
    sort(all(vs)), sort(all(vt));
    int ans = 0;
    int j = n - 1;
    for (int i = 0; i < n; i++) {
        while (j >= 0 && vs[i] + vt[j] + l > k) {
            j--;
        }
        ans += j + 1;
    }
    cout << ans;
}

signed main() {
    // freopen("qi.in", "r", stdin);
    // freopen("qi.out", "w", stdout);
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int test = 1;
    // cin >> test;
    while (test--) {
        solve();
        // cout << '\n';
    }
    return 0;
}

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