Submission #1158883

#	Time	Username	Problem	Language	Result	Execution time	Memory
1158883		vladilius	Railway Trip (JOI17_railway_trip)	C++20	20 / 100	2096 ms	17220 KiB

railway_trip

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#define pb push_back
#define ff first
#define ss second

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    
    int n, k, q; cin>>n>>k>>q;
    vector<int> a(n + 1), d[k + 1];
    for (int i = 1; i <= n; i++){
        cin>>a[i];
        d[a[i]].pb(i);
    }
    
    vector<int> g[n + 1];
    set<int> st;
    for (int i = k; i > 0; i--){
        for (int j: d[i]) st.insert(j);
        for (int j: d[i]){
            auto it = st.find(j);
            if (it != prev(st.end())){
                auto it1 = next(it);
                g[j].pb(*it1);
                g[*it1].pb(j);
            }
            if (it != st.begin()){
                auto it1 = prev(it);
                g[j].pb(*it1);
                g[*it1].pb(j);
            }
        }
    }

    while (q--){
        int x, y; cin>>x>>y;
        vector<int> dist(n + 1, 1e9);
        queue<int> q; dist[x] = -1; q.push(x);
        while (!q.empty()){
            int v = q.front(); q.pop();
            for (int u: g[v]){
                int f = dist[v] + 1;
                if (f < dist[u]){
                    dist[u] = f;
                    q.push(u);
                }
            }
        }
        cout<<dist[y]<<"\n";
    }
}

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3: 0 / 25
• Subtask 4: 0 / 55