Submission #1055034

#	Time	Username	Problem	Language	Result	Execution time	Memory
1055034		Gromp15	Stations (IOI20_stations)	C++17	52.32 / 100	552 ms	9072 KiB

stations

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

bool line = 1;
bool binary = 1;

const int N = 1001;
vector<vector<int>> go(N, vector<int>(N));

std::vector<int> label(int n, int k, std::vector<int> u, std::vector<int> v) {
	vector<vector<int>> adj(n);
	for (int i = 0; i < n-1; i++) {
		if (u[i] > v[i]) swap(u[i], v[i]);
		binary &= (v[i] + 1) / 2 == (u[i] + 1);
		adj[u[i]].push_back(v[i]);
		adj[v[i]].push_back(u[i]);
	}
	/*
	int r = -1;
	for (int i = 0; i < n; i++) {
		if (adj[i].size() == 1) r = i;
		line &= adj[i].size() <= 2;
	}
	if (line) {
		vector<int> ans(n);
		int t = 0;
		auto dfs = [&](auto&& s, int v, int p) -> void {
			ans[v] = t++;
			for (int u : adj[v]) if (u != p) s(s, u, v);
		};
		dfs(dfs, r, -1);
		return ans;
	}
	if (binary) {
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < n; j++) go[i][j] = -1;
			auto dfs = [&](auto&& s, int v) -> void {
				for (int u : adj[v]) if (u != go[i][v]) {
					go[i][u] = v;
					s(s, u);
				}
			};
			dfs(dfs, i);
		}
		vector<int> ans(n);
		iota(ans.begin(), ans.end(), 0);
		return ans;
	}
	*/
	vector<int> tin(n), tout(n);
	int timer = 0;
	auto dfs = [&](auto&& s, int v, int p) -> void {
		tin[v] = timer++;
		for (int u : adj[v]) if (u != p) {
			s(s, u, v);
		}
		tout[v] = timer - 1;
	};
	dfs(dfs, 0, -1);
	vector<int> ans(n);
	for (int i = 0; i < n; i++) ans[i] = tin[i] * 1000 + tout[i];
	return ans;
}

bool anc(int x, int y) {
	int tins = x / 1000, touts = x % 1000;
	int tint = y / 1000, toutt = y % 1000;
	return tins <= tint && toutt <= touts;
}

int find_next_station(int s, int t, std::vector<int> c) {
	/*
	if (line) {
		for (int x : c) if ((x-s)*(x-t) <= 0) return x;
	}
	*/
	/*
	if (binary) {
		return go[t][s];
	}
	*/
	if (anc(s, t)) {
		for (int x : c) {
			if (anc(s, x) && anc(x, t)) return x;
		}
	}
	else {
		for (int x : c) {
			if (anc(x, s)) return x;
		}
	}
	assert(0);
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 8
• Subtask 3: 16 / 16
• Subtask 4: 10 / 10
• Subtask 5: 26.3205 / 61