Submission #1201994

#	Time	Username	Problem	Language	Result	Execution time	Memory
1201994		ZsofiaKeresztely	Construction Project 2 (JOI24_ho_t2)	C++20	100 / 100	140 ms	24916 KiB

Main

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define pii pair<ll, ll>
#define fi first
#define se second
vector<vector<pii> > g;
vector<vector<ll> > d;

void dijkstra(ll start, ll type){
    priority_queue<pii> pq;
    pq.push({0, start});
    while (!pq.empty()){
        pii v = pq.top();
        pq.pop();
        //cout << "huhh" << v.se;
        if (d[type][v.se] >= 0) continue;
        d[type][v.se] = -v.fi;
        for (pii x : g[v.se]){
            if (d[type][x.fi] < 0){
                //cout << "huhi" << x.fi;
                pq.push({v.fi-x.se, x.fi});
            }
        }
    }
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    ll n, m, s, t, l, k;
    cin >> n >> m >> s >> t >> l >> k;
    g.resize(n+1);
    d.assign(2, vector<ll>(n+1, -1));
    while (m--){
        ll a, b, c;
        cin >> a >> b >> c;
        g[a].push_back({b, c});
        g[b].push_back({a, c});
    }
    dijkstra(s, 0);
    dijkstra(t, 1);
    /*for (ll i=0; i<=n; i++){
        cout << i << " " << d[0][i] << " " << d[1][i] << "\n";
    }*/
    if (d[0][t] >= 0 && d[0][t] <= k){
        cout << n * (n-1) / 2;
        return 0;
    }
    sort(d[0].begin(), d[0].end());
    sort(d[1].begin(), d[1].end());
    k -= l;
    ll pt = n, op = 0, nav = 0;
    while (nav < n && d[1][nav+1]){
        nav++;
    }
    for (ll i=1; i<=n; i++){
        if (d[0][i] == -1) continue;
        while (pt > nav && d[0][i] + d[1][pt] > k){
            pt--;
        }
        op += pt - nav;
    }
    cout << op;
}

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