Submission #833737

#	Time	Username	Problem	Language	Result	Execution time	Memory
833737		Johann	Stations (IOI20_stations)	C++14	76 / 100	908 ms	796 KiB

stations

#include "stations.h"
#include "bits/stdc++.h"
using namespace std;

typedef vector<int> vi;
typedef vector<vi> vvi;
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()

int N, K, idx;
vvi adj;
vi in, out, parity;
void dfs(int v, int p)
{
	in[v] = idx++;
	parity[v] = parity[p] ^ 1;
	for (int u : adj[v])
		if (u != p)
			dfs(u, v);
	out[v] = idx++;
};

std::vector<int> label(int n, int k, std::vector<int> u, std::vector<int> v)
{
	K = k;
	N = n;
	adj.clear();
	adj.resize(N);
	for (int i = 0; i < N - 1; ++i)
		adj[u[i]].push_back(v[i]), adj[v[i]].push_back(u[i]);
	idx = 0;
	in.assign(N, -1), out.assign(N, -1), parity.assign(N, 0);
	dfs(0, 0);

	vi labels(N);
	for (int i = 0; i < n; i++)
		labels[i] = (parity[i]) ? in[i] : out[i];

	return labels;
}

int find_next_station(int s, int t, std::vector<int> c)
{
	if (s < c[0])
	{
		// s has in parity
		if (t < s)
			return c.back(); // parent with highest out value
		for (int i = 0; i < sz(c); ++i)
		{
			if (t <= c[i])
				return c[i];
		}
		return c.back();
	}
	else
	{
		// s has out parity
		if (t > s)
			return c[0];
		for (int i = sz(c) - 1; i >= 0; --i)
			if (t >= c[i])
				return c[i];
		return c[0];
	}
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 8
• Subtask 3: 16 / 16
• Subtask 4: 10 / 10
• Subtask 5: 50 / 61