# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
1239816 | MarwenElarbi | Thousands Islands (IOI22_islands) | C++17 | 0 ms | 0 KiB |
#include <bits/stdc++.h>
#include "islands.h"
using namespace std;
#define fi first
#define se second
#define pb push_back
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
vector<int> adj[1005];
bool vis[1005];
bool test=false;
vector<int> ans;
bool dfs(int x,int p){
vis[x]=true;
ans.push_back(x);
if(adj[x].size()==3){
int a=-1,b=-1;
for(auto u : adj[x]){
if(u==p) continue;
if(a==-1) a=u;
else b=u;
}
ans.push_back(a);
ans.push_back(x);
ans.push_back(b);
ans.push_back(x);
ans.push_back(a);
ans.push_back(x);
ans.push_back(b);
ans.push_back(x);
return true;
}
bool test=false;
for(auto u:adj[x]){
if(vis[u]) continue;
if(dfs(u,x)){
test=true;
break;
}
}
if(!test) ans.pop_back();
else ans.push_back(x);
return test;
}
std::variant<bool, std::vector<int>> find_journey(
int N, int M, std::vector<int> U, std::vector<int> V) {
for (int i = 0; i < M; ++i)
{
adj[U[i]].push_back(V[i]);
}
if(adj[0].size()==2){
return vector<int>({0,adj[0][0],0,adj[0][1],0,adj[0][0],0,adj[0][1],0});
}
if(dfs(0)) return ans;
return false;
}