Submission #1181759

#	Time	Username	Problem	Language	Result	Execution time	Memory
1181759		TudorMa	Construction Project 2 (JOI24_ho_t2)	C++20	100 / 100	138 ms	26476 KiB

Main

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define fi first
#define sc second
#define pb push_back
#define int long long

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef double db;
typedef pair<int, int> pii;
template<typename type>
using ordered_set = tree<type, null_type, less<type>, rb_tree_tag, tree_order_statistics_node_update>;

const int N = 2e5 + 5, mod = 1e9 + 7, inf = 1e18;
const int dl[] = {-1, 0, 1, 0}, dc[] = {0, 1, 0, -1};
const int ddl[] = {-1, -1, -1, 0, 1, 1, 1, 0}, ddc[] = {-1, 0, 1, 1, 1, 0, -1, -1};

mt19937 gen(chrono::steady_clock::now().time_since_epoch().count());
int rng(int lo = 1, int hi = INT_MAX) {
    uniform_int_distribution<int> rnd(lo, hi);
    return rnd(gen);
}

struct mint {
    int val;
    mint(int32_t x = 0) {
        val = x % mod;
    }
    mint(long long x) {
        val = x % mod;
    }
    mint operator+(mint x) {
        return val + x.val;
    }
    mint operator-(mint x) {
        return val - x.val + mod;
    }
    mint operator*(mint x) {
        return 1LL * val * x.val;
    }
    void operator+=(mint x) {
        val = (*this + x).val;
    }
    void operator-=(mint x) {
        val = (*this - x).val;
    }
    void operator*=(mint x) {
        val = (*this * x).val;
    }
    friend auto operator>>(istream& in, mint &x) -> istream& {
        in >> x.val;
        x.val %= mod;
        return in;
    }
    friend auto operator<<(ostream& out, mint const &x) -> ostream& {
        out << x.val;
        return out;
    }
};

int n, m, s, t, l, k, ds[N], dt[N], w[N];
vector<pii> g[N];

void dijk(int start, int dst[]) {
    for(int i=1; i<=n; i++)
        dst[i] = inf;
    dst[start] = 0;
    priority_queue<pii, vector<pii>, greater<pii>> que;
    que.push({0, start});
    while(!que.empty()) {
        auto [d, nod] = que.top();
        que.pop();
        if(d != dst[nod])
            continue;
        
        for(auto &[id, nxt] : g[nod])
            if(dst[nxt] > d + w[id]) {
                dst[nxt] = d + w[id];
                que.push({dst[nxt], nxt});
            }
    }
}
int src(int x) {
    return upper_bound(dt+1, dt+n+1, x) - dt - 1;
}

int32_t main()
{
    cin.tie(nullptr)->sync_with_stdio(0);
    
    cin >> n >> m;
    cin >> s >> t >> l >> k;
    for(int i=1; i<=m; i++) {
        int x, y;
        cin >> x >> y >> w[i];
        g[x].pb({i, y});
        g[y].pb({i, x});
    }

    dijk(s, ds);
    dijk(t, dt);
    sort(dt+1, dt+n+1);

    if(ds[t] <= k) {
        cout << n * (n - 1) / 2;
        return 0;
    }

    int ans = 0;
    for(int i=1; i<=n; i++)
        ans += src(k-l-ds[i]);
    
    cout << ans;
    return 0;
}

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