Submission #1187318

#	Time	Username	Problem	Language	Result	Execution time	Memory
1187318		Zbyszek99	Construction Project 2 (JOI24_ho_t2)	C++20	100 / 100	366 ms	31204 KiB

Main

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define ull unsigned long long
#define ff first
#define ss second
#define pii pair<int,int>
#define pll pair<long long, long long>
#define vi vector<int>
#define vl vector<long long>
#define pb push_back
#define rep(i, b) for(int i = 0; i < (b); ++i)
#define rep2(i,a,b) for(int i = a; i <= (b); ++i)
#define rep3(i,a,b,c) for(int i = a; i <= (b); i+=c)
#define count_bits(x) __builtin_popcountll((x))
#define all(x) (x).begin(),(x).end()
#define siz(x) (int)(x).size()
#define forall(it,x) for(auto& it:(x))
using namespace __gnu_pbds;
using namespace std;
typedef tree<pair<long long,long long>, null_type, less<pair<long long,long long>>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;
//mt19937 mt;void random_start(){mt.seed(chrono::time_point_cast<chrono::milliseconds>(chrono::high_resolution_clock::now()).time_since_epoch().count());}
//ll los(ll a, ll b) {return a + (mt() % (b-a+1));}
const int INF = 1e9+50;
const ll INF_L = 1e18+40;
const ll MOD = 1e9+7;

ll dist[200'001][2];
vector<pll> graph[200'001];
int n,m,s,t;
ll L,K;

void dij(int start, int type)
{
    rep2(i,1,n) dist[i][type] = 1e18;
    priority_queue<pll,vector<pll>,greater<pll>> pq;
    pq.push({0,start});
    while(!pq.empty())
    {
        pll t = pq.top();
        pq.pop();
        if(dist[t.ss][type] != 1e18) continue;
        dist[t.ss][type] = t.ff;
        forall(it,graph[t.ss])
        {
            pq.push({t.ff+it.ss,it.ff});
        }
    }
}

int main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    //random_start();
    cin >> n >> m >> s >> t >> L >> K;
    rep(i,m)
    {
        int a,b,c;
        cin >> a >> b >> c;
        graph[a].pb({b,c});
        graph[b].pb({a,c});
    }
    dij(s,0);
    dij(t,1);
    if(dist[t][0] <= K)
    {
        cout << ((ll)n * (ll)(n-1)) / 2 << "\n";
        return 0;
    }
    ll ans = 0;
    ordered_set dists;
    rep2(i,1,n)
    {
        auto it = dists.upper_bound({K - (dist[i][0] + L),1e9});
        if(it != dists.begin())
        {
            it--;
            ans += dists.order_of_key(*it)+1;
        }
        dists.insert({dist[i][1],i});
    }
    dists = {};
    rep2(i,1,n)
    {
        auto it = dists.upper_bound({K - (dist[i][1] + L),1e9});
        if(it != dists.begin())
        {
            it--;
            ans += dists.order_of_key(*it)+1;
        }
        dists.insert({dist[i][0],i});
    }
    cout << ans << "\n";
}

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