#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    long long int n, i, j, k, l = 0, s, x, y, z = 0, r = 1000000001, rr = 0;
    cin >> n >> s >> k;
    long long int a[k];
    for (i = 0; i < k; i++) cin >> a[i];
    sort(a, a + k);
    for (i = 0; i < k; i++) {
      if (a[i] == s) z = 1;
    }
    if (z == 0)
      cout << "0" << endl;
    else if (z == 1 && k == 1)
      cout << "1" << endl;
    else {
      if (a[0] != 1) {
        r = std::min(r, s - (a[0] - 1));
        r = std::min(r, s - 1);
      }
      if (a[k - 1] != n) {
        r = std::min(r, (a[k - 1] + 1) - s);
        r = std::min(r, n - s);
      }
      for (i = 0; i < k - 1; i++) {
        if ((a[i + 1] - a[i]) > 1) {
          rr = a[i + 1] - 1;
          if (a[i] >= s) {
            rr = a[i] + 1;
            r = std::min(r, (rr - s));
          } else if (a[i + 1] <= s) {
            rr = a[i + 1] - 1;
            r = std::min(r, (s - rr));
          }
        }
      }
      cout << r << endl;
    }
  }
  return 0;
}
