#include <iostream>
#include <cmath>
#include <algorithm>
using namespace std;
int main ()
{
	int t; cin>>t;
	while (t--)
	{
		int broj=INT_MAX;
		int n,s,k; cin>>n>>s>>k;
		int a[k+1];
		bool akop[k+1]={false};
		for (int i=1; i<=k; i++)
		{
		cin>>a[i];
		akop[a[i]]=true;
		}
		sort (a,a+k);
		for (int i=1; i<=n; i++)
		{
			if (abs(s-i)<broj && !akop[i])
			{
				broj=abs(s-i);
			}
		}
		cout<<endl<<broj<<endl<<endl;
	}

	return 0;
}