Submission #1079201

#	Time	Username	Problem	Language	Result	Execution time	Memory
1079201		NourWael	Thousands Islands (IOI22_islands)	C++17	26 / 100	40 ms	12760 KiB

islands

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

int const mxN = 1e3+5;
vector<pair<int,int>> adj[mxN], adj2[mxN];
int n,m, cnt[mxN][mxN];
bool vis[mxN], poss[mxN];
vector<int> from[mxN];
bool flag = 0;
vector<int> st, fin;

void solve( int i , int p) {
  int fi=-1,se=-1,th=-1,fo=-1, n1 = 0,n2 = 0;
  for(auto it:adj[i]) {
    if(it.first==p) continue;
    if(fi==-1) { fi = it.second; n1 = it.first; }
    else if(se==-1) { se = it.second; n2 = it.first; }
  }
  
  for(auto it:adj[n1]) {
    if(it.first==i) {
      if(th==-1) th = it.second;
      else fo = it.second;
    }
  }

  for(auto it:adj[n2]) {
    if(it.first==i) {
      if(fo==-1) fo = it.second;
    }
  }

  fin = {fi,th,se,fo,th,fi,fo,se};

}

void dfs ( int i ) { 
  for(auto it:adj[i]) {
    if(vis[it.first]) continue;
    vis[it.first] = 1;
    st.push_back(it.second);
    if(adj[it.first].size()>2) { flag = 1; solve(it.first,i);  return; }
    dfs(it.first);
  }
}

variant<bool,vector<int>> find_journey( int N, int M,vector<int> U, vector<int> V) {
  
  n = N, m = M;
  for(int i=0; i<m; i++) { adj[U[i]].push_back({V[i],i}), adj2[V[i]].push_back({U[i],i}); cnt[U[i]][V[i]]++; }

  vector<int> v;
  if(adj[0].size()>1) { solve(0,-1); return fin; }
  else {
   vis[0] = 1; dfs(0);
  }
  if(flag) {
   vector<int> tot = st;
   for(auto it:fin) tot.push_back(it);
   reverse(st.begin(),st.end()); 
   for(auto it:st) tot.push_back(it);
   return tot;
  }
  return false;
}

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