graphHa.java

import java.io.*;
import java.util.*;

class graph{
   private int n;
   private LinkedList<Integer> adj[];
  // int[] arr;
   boolean visited[];
   graph(int n){
       this.n = n;
       adj = new LinkedList[n];

       for(int i = 0;i<n;i++){
           adj[i] = new LinkedList();
       }
      // arr = new int[n];
       visited = new boolean[n];

   }

   void addEdge(int a,int b){
       adj[a].add(b);
       adj[b].add(a);
   }

   int BFS(int s)
   {

       if(!visited[s]){
           LinkedList<Integer> queue = new LinkedList<Integer>();

           int k = 0;
           visited[s]=true;
           queue.add(s);


           while (queue.size() != 0)
           {

               s = queue.poll();

               Iterator<Integer> i = adj[s].listIterator();
               while (i.hasNext())
               {
                   int x = i.next();
                   if (!visited[x])
                   {
                     k++;

                       visited[x] = true;
                      // arr[x] =arr[s] + 1;
                       queue.add(x);
                   }
               }
           }

           return k;
       }else{
         return -1;
       }



   }




}


public class tree {

   public static void main(String[] args) {
      Scanner in = new Scanner(System.in);

      int t = in.nextInt();
      in.nextLine();

      for(int i = 0;i<t;i++){
        int n = in.nextInt();
        int m = in.nextInt();
        int cb = in.nextInt();
          int r = in.nextInt();

        graph g = new graph(n);


        for(int j = 0;j<m;j++){
          int a = in.nextInt();
          int b = in.nextInt();

              g.addEdge(a-1,b-1);


        }



           long sum = 0;
        for(int k = 0;k<n;k++){
          int p = g.BFS(k);
       // System.out.println(p +" " + k);
          if(p != -1){

                  sum += Math.min(p*r + cb, (p+1)*cb);
                //  c++;


          }


        }



        System.out.println(sum);

      }

   }


}