Submission #816081

#	Time	Username	Problem	Language	Result	Execution time	Memory
816081		Pikachu	Stations (IOI20_stations)	C++17	52.32 / 100	819 ms	768 KiB

stations

#include <bits/stdc++.h>
#include "stations.h"

using namespace std;

vector<int> label(int n, int k, vector<int> u, vector<int> v) 
{
	vector<int> labels(n);
    vector<vector<int> > adj(n);
    
    for (int i = 0; i < n - 1; i++) {
        adj[u[i]].push_back(v[i]);
        adj[v[i]].push_back(u[i]);
    }
	
    int ti = 0, to = 0;
    auto DFS = [&] (auto DFS, int u, int par) -> void
    {
        labels[u] = ti;
        ti++;
        for (int i = 0; i < (int)adj[u].size(); i++) {
            if (adj[u][i] == par) {
                adj[u].erase(adj[u].begin() + i); 
                break;
            }
        }

        if (adj[u].size()) {
            for (int i = 0; i < (int)adj[u].size() - 1; i++) {
                DFS(DFS, adj[u][i], u);
            }
            DFS(DFS, adj[u].back(), u);
        }

        labels[u] = labels[u] * 1000 + to;
        to++;
    };
    DFS(DFS, 0, -1);

	return labels;
}

int find_next_station(int s, int t, vector<int> c) 
{
    pair<int,int> st = {s / 1000, s % 1000};
    pair<int,int> en = {t / 1000, t % 1000};
    vector<pair<int,int> > adj;
    for (int x : c) {
        adj.push_back(make_pair(x / 1000, x % 1000));
    }
    pair<int,int> par = make_pair(-1, -1);
    if (st.first) {
        for (pair<int,int> p : adj) {
            if (!(st.first <= p.first && p.second <= st.second)) {
                par = p;
                break;
            }
        }
    }
    if (!(st.first <= en.first && en.second <= st.second)) return par.first * 1000 + par.second;
    for (pair<int,int> p : adj) {
        if (par == p) continue;
        if (p.first <= en.first && en.second <= p.second) return p.first * 1000 + p.second;
    }
    return -1;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 8
• Subtask 3: 16 / 16
• Subtask 4: 10 / 10
• Subtask 5: 26.3206 / 61