Submission #1126880

#	Time	Username	Problem	Language	Result	Execution time	Memory
1126880		fzyzzz_z	Construction Project 2 (JOI24_ho_t2)	C++20	100 / 100	207 ms	22184 KiB

Main

#include<bits/stdc++.h>

using namespace std;

using ll = long long;

#define pb push_back
#define all(x) (x).begin(),(x).end()

const ll INF = 1e18;

int main(){
    cin.tie( nullptr );
    ios::sync_with_stdio( false );
    cout << setprecision( 12 ) << fixed;

    ll n, m;
    cin >> n >> m;
    ll s, t, l, k;
    cin >> s >> t >> l >> k;
    --s;
    --t;
    vector<vector<pair<ll, ll>>> g(n);
    for(int i = 0; i < m; ++i){
        ll a, b, c;
        cin >> a >> b >> c;
        --a;
        --b;
        g[a].pb({b, c});
        g[b].pb({a, c});
    }
    vector<ll> dists(n, INF);
    dists[s] = 0;
    priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>> q;
    q.push({0, s});
    while(!(q.empty())){
        ll x = q.top().second;
        ll d = q.top().first;
        q.pop();
        if(dists[x] != d) continue;
        
        for(auto c: g[x]){
            if(dists[c.first] > d + c.second){
                dists[c.first] = d + c.second;
                q.push({d + c.second, c.first});
            }
        }
    }
    if(dists[t] <= k){
        cout << n * (n - 1) / 2 << endl;
        return 0;
    }
    vector<ll> distt(n, INF);
    distt[t] = 0;
    q.push({0, t});
    while(!(q.empty())){
        ll x = q.top().second;
        ll d = q.top().first;
        q.pop();
        if(distt[x] != d) continue;
        
        for(auto c: g[x]){
            if(distt[c.first] > d + c.second){
                distt[c.first] = d + c.second;
                q.push({d + c.second, c.first});
            }
        }
    }
    sort(all(distt));
    
    ll ans = 0;
    for(int i = 0; i < n; ++i){
        ans += upper_bound(all(distt), k - dists[i] - l) - distt.begin();
    }
    cout << ans << endl;
}

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