Submission #1058296

#	Time	Username	Problem	Language	Result	Execution time	Memory
1058296		tolbi	Thousands Islands (IOI22_islands)	C++17	5 / 100	112 ms	18608 KiB

islands

#include "islands.h"
#include <bits/stdc++.h>
using namespace std;
std::variant<bool, std::vector<int>> find_journey(
	int N, int M, std::vector<int> U, std::vector<int> V) {
	set<pair<int,int>> st;
	vector<vector<int>> arr(N);
	map<pair<int,int>,int> mp;
	for (int i = 0; i < M; i++){
		mp[{U[i],V[i]}]=i;
		if (st.find({V[i],U[i]})!=st.end()) continue;
		st.insert({U[i],V[i]});
		arr[U[i]].push_back(V[i]);
		arr[V[i]].push_back(U[i]);
	}
	if (arr[0].size()<=1) return false;
	vector<int> par(N,-1);
	vector<vector<int>> lol(N);
	queue<pair<int,int>> q;
	q.push({0,-2});
	while (q.size()){
		int node = q.front().first;
		int lnode = q.front().second;
		q.pop();
		if (par[node]!=-1) continue;
		if (lnode!=-2) lol[lnode].push_back(node);
		par[node]=lnode;
		for (auto it : arr[node]){
			q.push({it,node});
		}
	}
	vector<int> ans;
	bool boolean=false;
	function<void(int)> dfs = [&](int node){
		for (auto it : lol[node]){
			if (boolean){
				ans.push_back(mp[{it,node}]);
			}
			else ans.push_back(mp[{node,it}]);
			dfs(it);
			if (boolean){
				ans.push_back(mp[{node,it}]);
			}
			else ans.push_back(mp[{it,node}]);
		}
	};
	dfs(0);
	boolean=true;
	dfs(0);
	return ans;
}

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