Submission #1051493

#	Time	Username	Problem	Language	Result	Execution time	Memory
1051493		aykhn	Stations (IOI20_stations)	C++17	100 / 100	565 ms	1288 KiB

stations

#include "stations.h"
#include <bits/stdc++.h>
 
using namespace std;
 
const int MXN = 1e3 + 5;
 
int in[MXN], out[MXN], tim = -1;
vector<int> adj[MXN];
vector<int> labels;
 
void dfs(int a, int p, int w)
{
	in[a] = ++tim;
	for (int v : adj[a])
	{
		if (v == p) continue;
		dfs(v, a, w ^ 1);
	}
	out[a] = ++tim;
	if (w) labels[a] = in[a];
	else labels[a] = out[a];
}
 
vector<int> label(int n, int k, vector<int> u, vector<int> v) 
{
	tim = -1;
	for (int i = 0; i < n; i++)
	{
		in[i] = out[i] = 0;
		adj[i].clear();
	}
	for (int i = 0; i < n - 1; i++) adj[u[i]].push_back(v[i]), adj[v[i]].push_back(u[i]);
	labels.assign(n, 0);
	dfs(0, 0, 0);
	vector<array<int, 2>> v1;
	for (int i = 0; i < labels.size(); i++) v1.push_back({labels[i], i});
	sort(v1.begin(), v1.end());
	for (int i = 0; i < v1.size(); i++) labels[v1[i][1]] = i;
	return labels;
}
 
int find_next_station(int s, int t, vector<int> c)
{
	for (int x : c) if (x == t) return t;
	int sz = c.size();
	if (sz == 1) return c[0];
	else if (s < c[0])
	{
		if (!(s <= t && t <= c[sz - 2])) return c[sz - 1];
		c.pop_back();
		for (int x : c) if (t <= x) return x;
	}
	else
	{
		if (!(c[1] <= t && t <= s)) return c[0];
		c.erase(c.begin());
		reverse(c.begin(), c.end());
		for (int x : c) if (x <= t) return x;
	}
}

Compilation message (stderr)

stations.cpp: In function 'std::vector<int> label(int, int, std::vector<int>, std::vector<int>)':
stations.cpp:37:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   37 |  for (int i = 0; i < labels.size(); i++) v1.push_back({labels[i], i});
      |                  ~~^~~~~~~~~~~~~~~
stations.cpp:39:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 2> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   39 |  for (int i = 0; i < v1.size(); i++) labels[v1[i][1]] = i;
      |                  ~~^~~~~~~~~~~
stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:61:1: warning: control reaches end of non-void function [-Wreturn-type]
   61 | }
      | ^

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