Submission #1207985

#	Time	Username	Problem	Language	Result	Execution time	Memory
1207985		HappyCapybara	Thousands Islands (IOI22_islands)	C++20	0 / 100	1108 ms	527916 KiB

islands

#include "islands.h"
#include<bits/stdc++.h>
using namespace std;

variant<bool, vector<int>> find_journey(int N, int M, vector<int> U, vector<int> V){
  vector<vector<int>> g(N);
  for (int i=0; i<M; i+=2){
    g[U[i]].push_back(i);
    g[V[i]].push_back(i+1);
  }
  vector<int> p1, p2;
  int cur = 0, prev = 0;
  while (true){
    if (g[cur].size() == 0 || (g[cur].size() == 1 && cur != 0)) return false;
    if (g[cur].size() == 3 || (g[cur].size() == 2 && cur == 0)){
      break;
    }
    int next = U[g[cur][0]]+V[g[cur][0]]-cur;
    if (next == prev){
      next = U[g[cur][1]]+V[g[cur][1]]-cur;
      p1.push_back(g[cur][1]+(next == U[g[cur][1]]));
    }
    else p1.push_back(g[cur][0]+(next == U[g[cur][0]]));
    prev = cur;
    cur = next;
  }
  vector<int> res;
  for (int x : p1) res.push_back(x);
  for (int x : p2) res.push_back(x);
  reverse(p1.begin(), p1.end());
  for (int x : p1) res.push_back(x);
  return res;
}

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