#include <bits/stdc++.h>
using namespace std;
 
int main() {
	int t;
	cin >> t;
	while(t--)
	{
		int n,a;
		cin >> n >> a;
		vector<int > v;
		for(int i=0;i<n;i++)
		{
			int p;
			cin >> p;
			v.push_back(p);
		}
		int mid = v[0]+v[n-1];
		mid = mid/2;
		if(mid<a)
		{
			int r = (v[n-1]-a)*2;
			int w = a - v[0];
			int s = r+w;
			cout << s << endl;
		}
		else
		{
			int r = a-v[0]*2;
			int w = v[n-1] - a;
			int s = r+w;
			cout << s << endl;
		}
	}
	return 0;
}

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12
1 1
1
1 2
1
1 1
2
2 1
2 3
2 2
1 3
2 3
1 2
3 1
1 2 3
3 2
1 3 4
3 3
1 2 3
4 3
1 2 3 10
5 5
1 2 3 6 7
6 6
1 2 3 9 10 11