Submission #1287980

#	Time	Username	Problem	Language	Result	Execution time	Memory
1287980		crispxx	Stations (IOI20_stations)	C++20	52.32 / 100	403 ms	532 KiB

stations

#include "stations.h"

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

// #define int long long
#define all(x) x.begin(), x.end()
#define pb push_back
#define ar array
#define nl '\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++) {
		adj[u[i]].pb(v[i]);
		adj[v[i]].pb(u[i]);
	}
	
	vector<int> tin(n), tout(n);
	
	int timer = -1;
	
	auto dfs = [&](auto &&self, int v, int p) -> void {
		tin[v] = ++timer;
		for(auto to : adj[v]) {
			if(to == p) continue;
			self(self, to, v);
		}
		tout[v] = timer;
	};
	
	dfs(dfs, 0, 0);
	
	vector<int> lbl(n);
	
	for(int i = 0; i < n; i++) {
		// assert(tin[i] >= 0 && tin[i] < 1000);
		// assert(tout[i] >= 0 && tout[i] < 1000);
		lbl[i] = tin[i] * 1000 + tout[i];
		assert(lbl[i] >= 0 && lbl[i] <= k);
		// cout << i << ": " << tin[i] << ' ' << tout[i] << ' ' << lbl[i] << nl;
		// assert(lbl[i] >= 0 && lbl[i] < 1000000);
	}
	
	return lbl;
}

int find_next_station(int s, int t, std::vector<int> c) {
	auto check = [&](int u, int v) {
		int tinu = u / 1000;
		int toutu = u % 1000;
		int tinv = v / 1000;
		int toutv = v % 1000;
		return tinv >= tinu && toutv <= toutu;
	};
	
	if(check(s, t)) {
		for(auto &u : c) {
			if(check(u, t) && !check(u, s)) return u;
			// assert(!check(u, t));
		}
	} else {
		for(auto &u : c) {
			if(check(u, s)) return u;
			// assert(check(s, u));
		}
	}
	
	// return 1;
	
	assert(false);
}

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