Submission #954697

#	Time	Username	Problem	Language	Result	Execution time	Memory
954697		n1k	Thousands Islands (IOI22_islands)	C++17	1.75 / 100	68 ms	12064 KiB

islands

#include "islands.h"

#include <bits/stdc++.h>

using namespace std;

vector<vector<array<int, 2>>> g;
vector<set<int>> connected;
vector<int> color, par;

int x, y;


bool dfs(int u, int p){
	par[u] = p;
	color[u] = 1;
	for(auto [v, e]:g[u]){
		if(v==p)
			continue;
		if(color[v]){
			x = v;
			y = u;
			return true;
		}
		if(dfs(v, u)){
			return true;
		}
	}
	return false;
}

std::variant<bool, std::vector<int>> find_journey(int N, int M, std::vector<int> U, std::vector<int> V) {
	g.assign(N, {});
	connected.assign(N, {});
	color.assign(N, {});
	par.assign(N, {});

	for(int i=0; i<M; i++){
		if(connected[U[i]].count(V[i]))
			continue;

		g[U[i]].push_back({V[i], i});
		connected[U[i]].insert(V[i]);
	}

	return dfs(0, -1);
}

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