Submission #342051

#	Time	Username	Problem	Language	Result	Execution time	Memory
342051		SeDunion	Stations (IOI20_stations)	C++17	100 / 100	1111 ms	1380 KiB

stations

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

using namespace std;

vector<int> g[2002];

int tin[2002], tout[2002], timer;

void dfs(int v, vector<int> &labels, int p = -1, int d = 0) {
	if (!d) labels[v] = timer++;
	for (int to : g[v]) if (to != p) {
		dfs(to, labels, v, d ^ 1);
	}
	if (d) labels[v] = timer++;
}

std::vector<int> label(int n, int k, std::vector<int> u, std::vector<int> v) {
	std::vector<int> labels(n);
	for (int i = 0; i < n; i++) {
		g[i].clear();
	}
	timer = 0;
	for (int i = 0 ; i < n - 1 ; ++ i) {
		g[u[i]].push_back(v[i]);
		g[v[i]].push_back(u[i]);
	}
	dfs(1, labels);
	return labels;
}

bool upper(int ina, int outa, int inb, int outb) {
	return ina <= inb && outa >= outb;
}

int find_next_station(int s, int t, std::vector<int> c) {
	// upper(s, t) return s->c->t
	// return pred
	int m = (int)c.size();
	vector<int> din(m), dout(m);
	int sin, sout;
	if (s < c[0]) { // s->in
		sin = s;
		if (m > 1) sout = c[m - 2];
		else sout = s;
		if (sin <= t && t <= sout) {
			for (int i = 0 ; i < m - 1 ; ++ i) {
				if (c[i] >= t) return c[i];
			}
		} else {
			return c[m - 1];
		}
	} else {
		sout = s;
		if (m > 1) sin = c[1];
		else sin = s;
		if (sin <= t && t <= sout) {
			for (int i = m - 1 ; i > 0 ; -- i) {
				if (c[i] <= t) return c[i];
			}
		} else {
			return c[0];
		}
	}
	
}

Compilation message (stderr)

stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:40:19: warning: control reaches end of non-void function [-Wreturn-type]
   40 |  vector<int> din(m), dout(m);
      |                   ^

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