Submission #1051212

#	Time	Username	Problem	Language	Result	Execution time	Memory
1051212		Trent	Thousands Islands (IOI22_islands)	C++17	0 / 100	1095 ms	856 KiB

islands

#include "islands.h"
#include "bits/stdc++.h"
using namespace std;
#define forR(i, x) for(int i = 0; i < (x); ++i)
#define REP(i, a, b) for(int i = (a); i < (b); ++i)
#define all(x) x.begin(), x.end()
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vll;
typedef vector<bool> vb;

struct edge{int t, i;};
vector<vector<edge>> adj;
vi nStk, eStk;
vb oStk;
bool dfs(int c, vi& ans) {
  // nStk is [0, c), eStk is [0, c]
  if(oStk[c]) {
    for(int i : eStk) ans.push_back(i);
    for(int i : eStk) ans.push_back(i ^ 1);
    for(int i : eStk) ans.push_back(i);
    for(int i : eStk) ans.push_back(i ^ 1);
    return true;
  }
  oStk[c] = true;
  nStk.push_back(c);
  for(auto [t, i] : adj[c]) {
    eStk.push_back(i);
    if(dfs(t, ans)) return true;
    eStk.pop_back();
  }
  nStk.pop_back();
  oStk[c] = false;
  return false;
}
std::variant<bool, std::vector<int>> find_journey(
    int N, int M, std::vector<int> U, std::vector<int> V) {
      adj.resize(N);
      forR(i, M) {
        adj[U[i]].push_back({V[i], i});
      }
      oStk.resize(N);
      vi ans;
      bool done = dfs(0, ans);
      if(done) return ans;
      return false;
}

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