Submission #378252

#	Time	Username	Problem	Language	Result	Execution time	Memory
378252		KoD	Stations (IOI20_stations)	C++17	100 / 100	999 ms	1208 KiB

stations

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

template <class T>
using Vec = std::vector<T>;

Vec<int> label(int n, int k, Vec<int> u, Vec<int> v) {
	Vec<Vec<int>> graph(n);
	for (int i = 0; i < n - 1; ++i) {
		graph[u[i]].push_back(v[i]);
		graph[v[i]].push_back(u[i]);
	}
	int time = 0;
	Vec<int> ret(n);
	auto dfs = [&](auto dfs, const int u, const int p, const int d) -> void {
		const auto in = time++;
		for (const auto v: graph[u]) {
			if (v != p) {
				dfs(dfs, v, u, d + 1);
			}
		}
		const auto out = time++;
		ret[u] = (d % 2 == 0 ? in : out) / 2;
	};
	dfs(dfs, 0, -1, 0);
	return ret;
}

int find_next_station(int s, int t, Vec<int> c) {
	if (c.size() == 1) {
		return c[0];
	}
	std::sort(c.begin(), c.end());
	if (s == 0) {
		return *std::lower_bound(c.begin(), c.end(), t);
	}
	if (s < c.front()) {
		const auto p = c.back();
		c.pop_back();
		if (s < t && t <= c.back()) {
			return *std::lower_bound(c.begin(), c.end(), t);
		}
		else {
			return p;
		}
	}
	else {
		const auto p = c.front();
		c.erase(c.begin());
		if (c.front() <= t && t < s) {
			return *std::prev(std::upper_bound(c.begin(), c.end(), t));
		}
		else {
			return p;
		}
	}
}

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