614-A

/* package codechef; // don't place package name! */

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

/* Name of the class has to be "Main" only if the class is public. */
public final class Codechef
{
    public static int sol(int s,int n,HashSet<Integer> hs){
        int ans=0;
        if(!hs.contains(s))
            return ans;
        int p1=s,p2=s;
        while(p1>0 && p2<=n && ans<1001){
            if(!hs.contains(p1)){
                return ans;
            }
            p1--;
            if(!hs.contains(p2)){
                return ans;
            }
            p2++;
            ans++;
        }
        while(p1>0 && ans<1001){
            if(!hs.contains(p1)){
                return ans;
            }
            p1--;
            ans++;
        }
        while(p2<=n && ans<1001){
            if(!hs.contains(p2)){
                return ans;
            }
            p2++;
            ans++;
        }
        return ans;
    }
    public static void main (String[] args) throws java.lang.Exception
    {
        Scanner sc=new Scanner(System.in);
        int t=sc.nextInt();
        while(t>0){
            int n=sc.nextInt();
            int s=sc.nextInt();
            int k=sc.nextInt();
            HashSet<Integer> hs=new HashSet<>();
            while(k>0){
                hs.add(sc.nextInt());
                k--;
            }
            int ans=sol(s,n,hs);
            System.out.println(ans);
            t--;
        }
    }
}