Submission #772465

#	Time	Username	Problem	Language	Result	Execution time	Memory
772465		khshg	Stations (IOI20_stations)	C++14	52.32 / 100	718 ms	852 KiB

stations

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

vector<vector<int>> adj;
vector<int> L, R, sz;

void dfs(int s, int p, int low) {
	L[s] = low;
	sz[s] = 1;
	for(auto& u : adj[s]) {
		if(u == p) continue;
		dfs(u, s, low + sz[s] - 1);
		sz[s] += sz[u];
	}
	R[s] = low + sz[s] - 1;
}

pair<int, int> conv(int s) {
	return {s % 1000, s / 1000};
}
int conv(pair<int, int> s) {
	return s.first + s.second * 1000;
}

vector<int> label(int N, int K, vector<int> u, vector<int> v) {
	sz.resize(N);
	L.resize(N);
	R.resize(N);
	adj.resize(N);
	for(auto& I : adj) I.clear();
	for(int i = 0; i < (int)u.size(); ++i) {
		adj[u[i]].push_back(v[i]);
		adj[v[i]].push_back(u[i]);
	}
	dfs(0, -1, 0);
	vector<int> labels(N);
	for(int i = 0; i < N; ++i) labels[i] = conv({L[i], R[i]});
	return labels;
}

int find_next_station(int s, int t, vector<int> c) {
	pair<int, int> S = conv(s), T = conv(t);
	vector<pair<int, int>> C((int)c.size());
	for(int i = 0; i < (int)c.size(); ++i) C[i] = conv(c[i]);
	int par = -1, ans = -1;
	for(int i = 0; i < (int)c.size(); ++i) {
		if(C[i].first <= S.first && C[i].second >= S.second) par = i;
		else if(C[i].first <= T.second && C[i].second >= T.second) ans = i;
	}
	return (ans == -1 ? conv(C[par]) : conv(C[ans]));
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 8
• Subtask 3: 16 / 16
• Subtask 4: 10 / 10
• Subtask 5: 26.3244 / 61