Submission #985511

#	Time	Username	Problem	Language	Result	Execution time	Memory
985511		Maaxle	Stations (IOI20_stations)	C++17	0 / 100	582 ms	936 KiB

stations

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

#define range(it, a, b) for (ll it = a; it < b; it++)
#define all(x) begin(x), end(x)
#define ll long long
#define ull unsigned long long
#define INF64 ((ll) 1 << 62)
#define INF32 (1 << 30)
#define mset multiset
#define uset unordered_set
#define umap unordered_map 
#define pqueue priority_queue 
#define ptr(A) shared_ptr<A>

using namespace std;

static void dfs(int i, int p, int d, int& timer, vector<vector<int>>& adj, vector<int>& l) {    
    if (!(d & 1))
        l[i] = timer++;

    for (int& k : adj[i]) {
        if (k != p)
            dfs(k, i, d+1, timer, adj, l);
    }

    if (d & 1)  
        l[i] += timer++;
}

vector<int> label(int n, int k, vector<int> u, vector<int> v) {
    vector<vector<int>> adj (n);
    vector<int> l (n);

    range(i, 0, n-1) {
        adj[u[i]].push_back(v[i]);
        adj[v[i]].push_back(u[i]);
    }

    int timer = 0;
    dfs(0, -1, 0, timer, adj, l);
    return l;
}
		

int find_next_station(int s, int t, vector<int> c) {
    // CASE 1 -> s has an 'in' value
    // every node in c has value 'out'
    // the parent of them all is the right-most value
    // s is the left-most value
    if (s < c[0]) {

        // CASE 1.1 -> t is not a decendant of s
        // and t is before s
        if (t < s || c.size() == 1) 
            return c.back();
            
        // CASE 1.2 -> t may or not be decendant of s
        // ancestor of t is the first in c that is >= t
        return *lower_bound(all(c), t);
    }

    // CASE 2 -> s has an 'out' value
    // every node in c has value 'in'
    // the parent of them all is the left-most value
    // s is the right-most value
    
    // CASE 2.1 -> t is not a decendant of s
    //  and t is after s
    if (t > s || c.size() == 1) 
        return c[0];
    
    // CASE 2.2 -> t may or not be a decendant of s
    // ancestor of t is the first in c that is <= t (backwards)
    return *(--upper_bound(all(c), t));
}

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