func_code_string: #include <bits/stdc++.h>   using namespace std;   long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }   void solve() {     int n;     cin >> n;     vector<long long> a(n);     for (int i = 0; i < n; i++) cin >> a[i];     if (n == 1) {       cout <<  1 n ;       return;     }     vector<long long> difs(n - 1);     for (int i = 0; i < n - 1; i++) difs[i] = abs(a[i + 1] - a[i]);     vector<long long> cj(n);     vector<long long> fj(n);     cj[n - 1] = 0;     fj[n - 1] = 1;     long long res = 0;     for (int i = n - 2; i >= 0; i--) {       if (gcd(difs[i], fj[i + 1]) > 1) {         cj[i] = cj[i + 1] + 1;         fj[i] = gcd(difs[i], fj[i + 1]);       } else {         cj[i] = int(difs[i] > 1ll);         fj[i] = difs[i];         for (int k = 1; k < cj[i + 1]; k++) {           if (gcd(fj[i], difs[i + k]) > 1) {             cj[i]++;             fj[i] = gcd(fj[i], difs[i + k]);           } else             break;         }       }       res = max(res, cj[i]);     }     cout << res + 1 <<   n ;   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     int tst;     cin >> tst;     while (tst--) solve();     return 0;   }   