#include <bits/stdc++.h>   using namespace std;   void solve() {     int i, j, k, n, m, ans = 0, cnt = 0, sum = 0;     cin >> n;     int a[n];     for (int i = 0; i < n; i++) cin >> a[i];     vector<int> res;     res.push_back(a[0]);     int last = a[0], flag = 1;     for (int i = 1; i < n - 1;) {       if (abs(a[i] - last) + abs(a[i] - a[i + 1]) > abs(last - a[i + 1])) {         res.push_back(a[i]);         last = a[i];         i++;       } else         i++;     }     if (flag) res.push_back(a[n - 1]);     cout << res.size() <<   n ;     for (auto x : res) cout << x <<    ;     cout <<   n ;   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     int t;     cin >> t;     while (t--) {       solve();     }     return 0;   }   