Submission #1204578

#	Time	Username	Problem	Language	Result	Execution time	Memory
1204578		g4yuhg	Toll (BOI17_toll)	C++20	8 / 100	2225 ms	589824 KiB

toll

//Huyduocdithitp
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define endl '\n'
#define faster ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);

const ll INF = (ll)1e18;
const int N = 50004;

struct Query { ll u, v; } qr[N];

ll k, n, m, q;
ll kq[N];
vector<pair<ll,ll>> adj[N];
set<ll> mp1[N], mp2[N];
ll mx = 0;
map<ll, ll> state[N];

int main() {
    faster;
    cin >> k >> n >> m >> q;
    mx = n / k;
    for (int i = 1; i <= m; i++) {
        ll u, v, w;
        cin >> u >> v >> w;
        adj[u].push_back({v, w});
    }
    for (int i = 1; i <= q; i++) {
        cin >> qr[i].u >> qr[i].v;
        if (qr[i].u / k >= qr[i].v / k) {
            kq[i] = -1;
        } else {
            kq[i] = INF;
            mp1[qr[i].u].insert(i);
            mp2[qr[i].v].insert(i);
        }
    }
    for (int id = 0; id <= mx; id++) {
        int L = id * k;
        int R = min<ll>(n, (id + 1) * k);
        for (int u = L; u <= R; u++) {
            // process queries ending at u
            for (auto it : mp2[u]) {
                auto itState = state[u].find(it);
                if (itState != state[u].end()) {
                    kq[it] = min(kq[it], itState->second);
                    state[u].erase(itState);
                }
            }
            // add queries starting at u
            for (auto it : mp1[u]) {
                state[u][it] = 0;
            }
            // relax along outgoing edges
            for (auto &edge : adj[u]) {
                ll v = edge.first;
                ll w = edge.second;
                for (auto &pr : state[u]) {
                    ll qi = pr.first;
                    ll val = pr.second + w;
                    auto it2 = state[v].find(qi);
                    if (it2 == state[v].end()) state[v][qi] = val;
                    else it2->second = min(it2->second, val);
                }
            }
        }
    }
    for (int i = 1; i <= q; i++) {
        cout << (kq[i] >= INF ? -1 : kq[i]) << endl;
    }
    return 0;
}

• Subtask 1: 0 / 7
• Subtask 2: 0 / 10
• Subtask 3: 8 / 8
• Subtask 4: 0 / 31
• Subtask 5: 0 / 44