Submission #1034629

#	Time	Username	Problem	Language	Result	Execution time	Memory
1034629		Mr_Husanboy	Thousands Islands (IOI22_islands)	C++17	27.75 / 100	21 ms	5468 KiB

islands

#include "islands.h"

#include <variant>
#include <bits/stdc++.h>

using namespace std;

#define ff first
#define ss second
#define all(a) (a).begin(), (a).end()
#define ll long long
const int mod = 1000002022;

vector<int> state, p;
int n, m; 
vector<vector<int>> g;
template<typename T>
int len(T &a){return a.size();}

mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());


variant<bool, vector<int>> find_journey(
    int n, int m, std::vector<int> u, std::vector<int> v) {
  vector<vector<int>> g(n);
  for(int i = 0; i < m; i ++) g[u[i]].push_back(i);
  if(len(g[0]) == 0) return false;

  if(n == 2){
    if(len(g[0]) <= 1) return false;
    if(len(g[1]) == 0) return false;
    return vector {g[0][0], g[1][0], g[0][1], g[0][0], g[1][0], g[0][1]};
  }

  if(len(g[0]) == 2){
    int a = g[0][0], b = g[0][1];
    return vector{a, a ^ 1, b, b ^ 1, a ^ 1, a, b ^ 1, b};
  }
  vector<int> ans = {g[0][0]};
  int cnt = 0;
  vector<int> cyc;
  while(true){
    int cur = v[ans.back()];
    cnt ++;
    if(len(g[cur]) <= 1){
      return false;
    }
    if(len(g[cur]) >= 3){
      vector<int> v;
      for(int j = 0; j < 3; j ++) if(g[cur][j] != (ans.back() ^ 1)) v.push_back(g[cur][j]);
      int a = v[0], b = v[1];
      cyc = vector{a, a ^ 1, b, b ^ 1, a ^ 1, a, b ^ 1, b};
      break;
    }
    if(g[cur][0] == (ans.back() ^ 1)){
      ans.push_back(g[cur][1]);
    }else ans.push_back(g[cur][0]);
  }
  vector<int> res = ans;
  for(auto u : cyc) res.push_back(u);
  reverse(all(ans));
  for(auto u : ans) res.push_back(u);
  return res;
}

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