Ice cream

#include <vector>
#include <iostream>
#include <unordered_map>
#include <algorithm>
#include <unordered_set>

using namespace std;
using ll = long long;

vector<ll> icecreams;
unordered_map<ll, vector<ll>> connections;

namespace std {

template<typename a, typename b>
struct hash< std::pair<a, b> > {
private:
   const hash<a> ah;
   const hash<b> bh;
public:
   hash() : ah(), bh() {}
   size_t operator()(const std::pair<a, b> &p) const {
      return ah(p.first) ^ bh(p.second);
   }
};

} // namespaces

void recursion(ll city, unordered_set<ll>& hasaccess, unordered_set<ll>& visited)
{
    if (visited.count(city) == 1) return;
    hasaccess.insert(icecreams.at(city-1));
    visited.insert(city);
    
    for (const ll dst : connections[city])
    {
        recursion(dst, hasaccess, visited);
    }
}

void connectRoads(const ll a, const ll b, unordered_set<std::pair<ll,ll>>& visited)
{
    const auto p = std::make_pair(a,b);
    if (visited.count(p) == 1) return;
    visited.insert(p);
    
    for (const ll neighborOfA : connections[a])
        connectRoads(neighborOfA, b, visited);
    
    for (const ll neighborOfB : connections[b])
        connectRoads(a, neighborOfB, visited);
        
    connections[a].push_back(b);
    connections[b].push_back(a);
}

int main()
{
    ll n,m;
    cin>>n>>m;
    icecreams.resize(n);
    for (int i=0; i<n; ++i)
        cin>>icecreams.at(i);
        
    
    for (int i=0; i<m; ++i)
    {
        ll a,b;
        cin>>a>>b;
        
        unordered_set<std::pair<ll,ll>> visited;
        connectRoads(a,b,visited);
    }
    
    for (int i=1; i<=n; ++i)
    {
        unordered_set<ll> hasaccess;
        unordered_set<ll> visited;
        
        recursion(i, hasaccess, visited);
        
        cout << hasaccess.size() << ' ';
    }
    cout << '\n';
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: TIME LIMIT EXCEEDED

Test 3

Verdict: TIME LIMIT EXCEEDED

Test 4

Verdict: TIME LIMIT EXCEEDED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: TIME LIMIT EXCEEDED

Test 8

Verdict: TIME LIMIT EXCEEDED

Test 9

Verdict: TIME LIMIT EXCEEDED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: TIME LIMIT EXCEEDED

Test 13

Verdict: TIME LIMIT EXCEEDED

Test 14

Verdict: TIME LIMIT EXCEEDED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: TIME LIMIT EXCEEDED

Test 18

Verdict: TIME LIMIT EXCEEDED

Test 19

Verdict: TIME LIMIT EXCEEDED

Test 20

Verdict: ACCEPTED