Submission #1061685

#	Time	Username	Problem	Language	Result	Execution time	Memory
1061685		jamjanek	Thousands Islands (IOI22_islands)	C++17	8.40 / 100	36 ms	7276 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;
bool czy[100010];
vector<int>stos2;
void dfs(int x, int kra){
	czy[x] = 1;
	stos2.push_back(x);
	/*
	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());
			stos.pop_back();
		}
		return;
	}*/
	
	for(auto j: graf[x]){
		if(kra/2!=j.second/2){
			odw[j.first]++;
			if(czy[j.first]){
				
				ans = stos;
				ans.push_back(j.second);
				vector<int>pomstos = {j.second^1};
				while(stos2.back()!=j.first){
					pomstos.push_back(stos.back());
					stos.pop_back();
					stos2.pop_back();
				}
				for(auto j: pomstos)ans.push_back(j^1);
				reverse(pomstos.begin(), pomstos.end());
				for(auto j: pomstos)ans.push_back(j);
				for(auto j: pomstos)ans.push_back(j^1);
				while(stos.size()){
					ans.push_back(stos.back());
					stos.pop_back();
				}
				
				return;
			}
			if(odw[j.first]==1){
				stos.push_back(j.second);
				dfs(j.first, j.second);
				if(ans.size())return;
				stos.pop_back();
			}
		}
	}
	czy[x] = 0;
	stos2.pop_back();
}
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});
	}
	odw[0] = 1;
	dfs(0, -2);
	if(ans.size()>0)return true;
	return false;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 5
• Subtask 3: 0 / 21
• Subtask 4: 8.399999999999999 / 24
• Subtask 5: 0 / 45