#include<bits/stdc++.h>
using namespace std;

int main()
{
    long long int test,n,s,i,k,p;
    cin>>test;
    while(test--)
    {
        cin>>n>>s>>k;
        long long int arr[n+1]= {0};
         ans1=n+1,ans2=n+1;

        while(k--)
        {
            cin>>p;
            arr[p]=1;
        }

        for(i=s; i<=n; ++i)
        {
            if(arr[i]==0)
            {
                i=abs(s-i);
                ans1=i;
                break;
            }
        }

        for(i=s; i>=1; --i)
        {
            if(arr[i]==0)
            {
                i=abs(s-i);
                ans2=i;
                break;
            }
        }

        cout<<min(ans1,ans2)<<endl;

    }
}