Submission #1074346

#	Time	Username	Problem	Language	Result	Execution time	Memory
1074346		fv3	Thousands Islands (IOI22_islands)	C++17	9.10 / 100	32 ms	6740 KiB

islands

#include "islands.h"
#include <bits/stdc++.h>

using namespace std;
vector<vector<pair<int, int>>> adj;
vector<int> res;
bool ok;

void DFS(int index, int last)
{
  if (adj[index].size() > 2)
  {
    ok = true;
    return;
  }

  for (auto node : adj[index])
  {
    if (node.first == last) continue;
    res.push_back(node.second);
    DFS(node.first, index);
    break;
  }
}

variant<bool, vector<int>> find_journey(int N, int M, vector<int> U, vector<int> V) 
{
  adj = vector<vector<pair<int, int>>>(N);
  res = vector<int>();
  for (int i = 0; i < M; i++)
  {
    adj[U[i]].push_back({V[i], i});
  }

  if (adj[0].size() > 1)
  {
    int s_out = adj[0][0].second;
    int s_in = s_out^1;

    int e_out = adj[0][1].second;
    int e_in = e_out^1;

    return vector<int>({s_out, s_in, e_out, e_in, s_in, s_out, e_in, e_out});
  }

  ok = false;
  DFS(0, -1);

  if (ok)
    return vector<int>({99});
  return false;

}

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