test 6 - 2022-2023 - Преброяване на области

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <unordered_map>
#include <set>

using namespace std;

void dfs(unordered_map<int, set<int>>& graph, vector<bool>& visited, int start){
    visited[start] = true;
    for(int neighbour : graph[start]){
        if(!visited[neighbour])
            dfs(graph, visited, neighbour);
    }
}

int test(){
    int x, y, a, b;
    cin >> x >> y;
    vector<bool> visited(x, false);
    unordered_map<int, set<int>> graph;
    for(int i = 0; i < y; i++){
        cin >> a >> b;
        graph[a].insert(b);
        graph[b].insert(a);
    }

    int counter = 0;
    for(int i = 0; i < x; i++){
        if(!visited[i]){
            counter++;
            dfs(graph, visited, i);
        }
    }
    return counter;
}

int main() {
    int t;
    cin >> t;
    for(int i = 0; i < t; i++){
        cout << test() << " ";
    }
    return 0;
}