Submission #1061980

#	Time	Username	Problem	Language	Result	Execution time	Memory
1061980		VMaksimoski008	Toll (BOI17_toll)	C++17	7 / 100	40 ms	6916 KiB

toll

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
 
const int maxn = 5e4 + 5;
 
int K, N, M, Q, B[maxn];
vector<ll> ans, dist(maxn);
vector<pii> g1[maxn], g2[maxn];
 
void D(int s, int l, int r) {
    for(int i=0; i<N; i++) dist[i] = 1e18;
    dist[s] = 0;
    priority_queue<pll, vector<pll>, greater<pll> > pq;
    
    pq.push({ 0, s });
    while(!pq.empty()) {
        auto [d, u] = pq.top(); pq.pop();
        if(d != dist[u]) continue;
        
        for(auto &[v, w] : g1[u]) {
            if(B[v] < l || B[v] > r) continue;
            if(dist[v] > dist[u] + w) {
                dist[v] = d + w;
                pq.push({ d + w, v });
            }
        }
    }
 
    pq.push({ 0, s });
    while(!pq.empty()) {
        auto [d, u] = pq.top(); pq.pop();
        if(d != dist[u]) continue;
        
        for(auto &[v, w] : g2[u]) {
            if(B[v] < l || B[v] > r) continue;
            if(dist[v] > dist[u] + w) {
                dist[v] = d + w;
                pq.push({ d + w, v });
            }
        }
    }
}
 
void f(int l, int r, vector<array<int, 3> > &qus) {
    if(l > r || qus.empty()) return ;
 
    int tm = (l + r) / 2;
    vector<array<int, 3> > L, R;
 
    for(int i=tm*K; i<min(N, tm * K + K); i++) {
        D(i, l, r);
        for(auto &[a, b, id] : qus) ans[id] = min(ans[id], dist[a] + dist[b]);
    }
 
    for(auto i=0; i<qus.size(); i++) {
        if(B[qus[i][1]] < tm) L.push_back(qus[i]);
        if(B[qus[i][0]] > tm) R.push_back(qus[i]);
    } 
 
    f(l, tm-1, L);
    f(tm+1, r, R);
}
 
signed main() {
    ios_base::sync_with_stdio(false);
    cout.tie(0); cin.tie(0);
    
    cin >> K >> N >> M >> Q;
    for(int i=0; i<N; i++) B[i] = i / K;
 
    ans.resize(Q, 1e18);
    vector<array<int, 3> > qus;
 
    for(int i=0; i<M; i++) {
        int a, b, t;
        cin >> a >> b >> t;
        g1[a].push_back({ b, t });
        g2[b].push_back({ a, t });
    }
 
    for(int i=0; i<Q; i++) {
        int a, b; cin >> a >> b;
        if(B[a] == B[b]) ans[i] = -1;
        else qus.push_back({ a, b, i });
    }
 
    f(0, B[N-1], qus);
    for(auto x : ans) cout << (x >= 1e18 ? -1 : x) << '\n';
    return 0;
}

Compilation message (stderr)

toll.cpp: In function 'void f(int, int, std::vector<std::array<int, 3> >&)':
toll.cpp:58:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 3> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |     for(auto i=0; i<qus.size(); i++) {
      |                   ~^~~~~~~~~~~

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