number of connected components (using dfs/adjacency matrix)

#include <bits/stdc++.h>
using namespace std;
int n;
const int MN=1e5+10;
bool visited[MN];
vector<int> adj_list[MN];
void dfs(int x){
    visited[x]=true;
    for (int u:adj_list[x]){
        if (!visited[u]){
            dfs(u);
        }
    }
}
int connected_components(){
    int counter=0;
    for (int i=1; i<=n; i++){
        if (!visited[i]){
            counter++;
            dfs(i);
        }
    }
    return counter;
}
int main()
{
    int t;
    cin>>t;
    while(t--){
        cin>>n;
        int a[100][100];
        for (int i=1; i<=n; i++){
            for (int j=1; j<=n; j++){
                cin>>a[i][j];
                if (a[i][j]==1){
                    adj_list[i].push_back(j);
                }
            }
        }
        cout<<connected_components<<"\n";
    }
}