Submission #835083

#	Time	Username	Problem	Language	Result	Execution time	Memory
835083		welleyth	Stations (IOI20_stations)	C++17	0 / 100	3039 ms	2097152 KiB

stations

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

constexpr int N = (int)2e3 + 1;

int tin[N],tout[N];
int timer = 0;

vector<int> g[N];

mt19937 rnd(time(nullptr));

void dfs(int v,int pr = -1){
	tin[v] = timer++;
	for(auto& to : g[v]){
		if(to == pr) continue;
		dfs(to,v);
	}
	tout[v] = timer++;
	return;
}

std::vector<int> label(int n, int k, std::vector<int> u, std::vector<int> v) {
	for(int i = 0; i < n-1; i++){
		g[u[i]].push_back(v[i]);
		g[v[i]].push_back(u[i]);
	}
	dfs(0);
	vector<int> labels(n);
	for(int i = 0; i < n; i++){
		labels[i] = tin[i] * N + tout[i];
	}
	return labels;
}

bool upper(int tinA,int toutA,int tinB,int toutB){
	return tinA <= tinB && toutA >= toutB;
}

int find_next_station(int s, int t, std::vector<int> c) {
	int tinS = s / N, toutS = s % N;
	int tinT = t / N, toutT = t % N;
	int pr = 0;
	for(auto& to : c){
		int tin = to / N, tout = to % N;
		if(upper(tin,tout,tinS,toutS)){
			pr = to;
			continue;
		}
		if(upper(tin,tout,tinT,toutT))
			return to;
	}
	return pr;
}

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