Submission #580970

#	Time	Username	Problem	Language	Result	Execution time	Memory
580970		Jomnoi	Stations (IOI20_stations)	C++17	0 / 100	847 ms	660 KiB

stations

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

const int MAX_N = 1005;

int N, timer;
vector <int> graph[MAX_N];
int depth[MAX_N], st[MAX_N], en[MAX_N];

void init(int n) {
	N = n, timer = 0;
	for(int i = 0; i < N; i++) {
		st[i] = en[i] = 0;
		graph[i].clear();
	}
}

void dfs(int u, int p) {
	st[u] = timer++;
	for(auto v : graph[u]) {
		if(v != p) {
			depth[v] = depth[u] + 1;
			dfs(v, u);
		}
	}
	en[u] = timer++;
}

vector <int> label(int n, int k, vector <int> u, vector <int> v) {
	init(n);

	for(int i = 0; i < N - 1; i++) {
		graph[u[i]].push_back(v[i]);
		graph[v[i]].push_back(u[i]);
	}

	dfs(0, -1);

	vector <int> S, T;
	for(int i = 0; i < N; i++) {
		if(depth[i] % 2 == 0) {
			S.push_back(st[i]);
		}
		else {
			T.push_back(en[i]);
		}
	}

	sort(S.begin(), S.end());
	sort(T.begin(), T.end());

	vector <int> labels(N);
	for(int i = 0; i < N; i++) {
		if(depth[i] % 2 == 0) {
			labels[i] = lower_bound(S.begin(), S.end(), st[i]) - S.begin();
		}
		else {
			labels[i] = lower_bound(T.begin(), T.end(), en[i]) - T.begin() + S.size();
		}
	}
	return labels;
}

int find_next_station(int s, int t, vector <int> c) {
	if(c[0] > s) { // s is labeled with st
		if(t < s) {
			return c.back();
		}
		for(int i = 0; i < c.size(); i++) {
			if(t <= c[i]) {
				return c[i];
			}
		}
		return c.back();
	}
	else { // s is labeled with en
		if(t > s) {
			return c[0];
		}
		for(int i = c.size() - 1; i >= 0; i--) {
			if(t >= c[i]) {
				return c[i];
			}
		}
		return c[0];
	}
}

Compilation message (stderr)

stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:70:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   70 |   for(int i = 0; i < c.size(); i++) {
      |                  ~~^~~~~~~~~~

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