Submission #1061633

#	Time	Username	Problem	Language	Result	Execution time	Memory
1061633		jamjanek	Thousands Islands (IOI22_islands)	C++17	9.10 / 100	40 ms	7632 KiB

islands

#include "islands.h"

#include <variant>
#include <vector>
#include<bits/stdc++.h>
using namespace std;

int odw[100010];
vector<pair<int, int>>graf[100010];
vector<int>ans;
vector<int>stos;
void dfs(int x, int kra){
	if(graf[x].size()>2){
		int pom = graf[x][0].second, pom1 = graf[x][1].second;
		if(pom/2==kra/2)
			pom = graf[x][2].second;
		if(pom1/2==kra/2)
			pom1 = graf[x][2].second;
		ans = stos;
		vector<int>POM = {pom, pom^1, pom1, pom1^1, pom^1, pom, pom1^1, pom1};
		for(auto j: POM)
			ans.push_back(j);
		while(stos.size()){
			ans.push_back(stos.back()^1);
			stos.pop_back();
		}
		return;
	}
	for(auto j: graf[x]){
		if(kra/2!=j.second/2){
			odw[j.first]++;
			if(odw[j.first]==1){
				stos.push_back(j.second);
				dfs(j.first, j.second);
				stos.pop_back();
			}
			if(ans.size())return;
		}
	}
}
std::variant<bool, std::vector<int>> find_journey(int n, int m, std::vector<int> U, std::vector<int> V) {
	
	int i;
	for(i=0;i<m;i+=2){
		graf[U[i]].push_back({V[i], i});
		graf[V[i]].push_back({U[i], i+1});
	}
	if(graf[0].size()>1 && ans.size()==0){
		ans = {graf[0][0].second, graf[0][0].second^1, graf[0][1].second, graf[0][1].second^1, graf[0][0].second^1, graf[0][0].second^1^1, graf[0][1].second^1, graf[0][1].second^1^1,};
		return ans;
	}
	odw[0] = 1;
	dfs(0, -2);
	if(ans.size()>0)return ans;
	return false;
}

• Subtask 1: 0 / 5
• Subtask 2: 1.75 / 5
• Subtask 3: 7.35 / 21
• Subtask 4: 0 / 24
• Subtask 5: 0 / 45