Submission #1031121

#	Time	Username	Problem	Language	Result	Execution time	Memory
1031121		happy_node	Stations (IOI20_stations)	C++17	100 / 100	627 ms	1304 KiB

stations

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

const int MX=1005;

vector<int> adj[MX];

int cnt=0;

vector<int> tin, tout, dep;

void dfs(int v, int p) {
	tin[v]=cnt++;
	for(auto u:adj[v]) {
		if(u==p) continue;
		dep[u]=dep[v]+1;
		dfs(u,v);
	}
	tout[v]=cnt++;
}

std::vector<int> label(int N, int K, std::vector<int> u, std::vector<int> v) {
	for(int i=0;i<N;i++) 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]);
	}

	cnt=0;
	tin.assign(N,0);
	tout.assign(N,0);
	dep.assign(N,0);
	dfs(0,-1);

	vector<pair<int,int>> res;
	for(int i=0;i<N;i++) {
		if(dep[i]&1) res.push_back({tin[i],i});
		else res.push_back({tout[i],i});
	}

	sort(res.begin(),res.end());	

	vector<int> ans(N);
	for(int i=0;i<N;i++) ans[res[i].second]=i; 

	return ans;
}

int find_next_station(int s, int t, std::vector<int> c) {
	bool ok=1;
	for(auto x:c) ok&=s<=x;

	if(ok) { // s itu tin
		int cur=s;
		for(int i=0;i+1<c.size();i++) {
			if(cur<t && t<=c[i]) { // c_i is tout
				return c[i];
			}
			cur=c[i];
		}
		return c.back();
	} else { // s itu tout
		c.push_back(s);
		for(int i=1;i+1<c.size();i++) {
			if(c[i]<=t && t<c[i+1]) {
				return c[i];
			}
		}
		return c[0];
	}
}

Compilation message (stderr)

stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:57:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |   for(int i=0;i+1<c.size();i++) {
      |               ~~~^~~~~~~~~
stations.cpp:66:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   66 |   for(int i=1;i+1<c.size();i++) {
      |               ~~~^~~~~~~~~

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