Submission #1054807

#	Time	Username	Problem	Language	Result	Execution time	Memory
1054807		LittleOrange	Stations (IOI20_stations)	C++17	100 / 100	563 ms	1272 KiB

stations

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

std::vector<int> label(int n, int k, std::vector<int> u, std::vector<int> v) {
	vector<ll> labels(n);
	iota(labels.begin(),labels.end(),0);
	vector<vector<ll>> con(n);
	for(ll i = 0;i<n-1;i++){
		con[u[i]].push_back(v[i]);
		con[v[i]].push_back(u[i]);
	}
	fill(labels.begin(),labels.end(),-1);
	/*for(ll i = 0;i<n;i++){
		if (con[i].size()==1&&labels[i]==-1){
			ll cur = i;
			ll it = 0;
			while(cur!=-1){
				labels[cur] = it++;
				ll nxt = -1;
				for(ll j : con[cur]) if (labels[j]==-1) nxt = j;
				cur = nxt;
			}
		}
	}*/
	/*ll rt = 0;
	for(ll i = 0;i<n;i++) if(con[i].size()>2) rt = i;
	labels[rt] = 0;
	ll gp = 0;
	for(ll i : con[rt]){
		ll g = (++gp)*1000;
		ll x = i;
		while(x!=-1){
			labels[x] = g++;
			ll nw = -1;
			for(ll j : con[x]){
				if(labels[j]==-1){
					nw = j;
				}
			}
			x = nw;
		}
	}*/
	vector<vector<ll>> ch(n);
	vector<ll> sz(n,1);
	{
		function<void(ll,ll)> dfs;
		dfs = [&](ll i, ll p){
			for(ll j : con[i]) if(j!=p){
				ch[i].push_back(j);
				dfs(j,i);
				sz[i]+=sz[j];
			}
		};
		dfs(0,-1);
	}
	{
		function<void(ll,ll,ll)> dfs;
		dfs = [&](ll i, ll it,ll pos){
			if (pos){
				labels[i] = it+sz[i]-1;
			}else{
				labels[i] = it++;
			}
			for(ll j : ch[i]){
				dfs(j, it, pos^1);
				it += sz[j];
			}
		};
		dfs(0,0,0);
	}
	//for(ll i = 0;i<n;i++) cerr << labels[i] << " \n"[i+1==n];
	return labels;
}

int find_next_station(int s, int t, std::vector<int> C) {
	deque<ll> c(C.begin(),C.end());
	//cerr << s << " " << t << " :";
	//for(ll i : c) cerr << " " << i;
	//cerr << "\n";
	/*s++;t++;
	ll lgs = __lg(s), lgt = __lg(t);
	if (lgs<lgt){
		ll x = t>>(lgt-lgs);
		if (s==x){
			return (t>>(lgt-lgs-1))-1;
		}
	}
	return (s>>1)-1;*/
	/*if (t>s) return s+1;
	else return s-1;*/
	/*ll gs = s/1000;
	ll gt = t/1000;
	if (gs==0){
		for(ll i : c){
			if (i/1000==gt) return i;
		}
	}else if(gs==gt){
		if(s>t){
			for(ll i : c){
				if (i<s) return i;
			}
		}else{
			for(ll i : c){
				if (i>s) return i;
			}
		}
	}else{
		for(ll i : c){
			if (i<s) return i;
		}
	}*/
	sort(c.begin(),c.end());
	if(s==0){
		for(ll i : c) if(i>=t) return i;
	}else{
		if (s<c[0]){
			ll pa = c.back();c.pop_back();
			if (t<s||c.empty()||t>c.back()) return pa;
			for(ll i : c) if(i>=t) return i;
		}else{
			ll pa = c.front();c.pop_front();
			if (t>s||c.empty()||t<c.front()) return pa;
			reverse(c.begin(),c.end());
			for(ll i : c) if(i<=t) return i;
		}
	}
	return -1;
}

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