三行dfs即可
#include <iostream>
using namespace std;
const int N = 16;
int a[N];
int dfs(int l, int r){
for (int i = l + 1; i < r; i ++ )
if (a[i] < a[i - 1]) return max(dfs(l, l + r >> 1), dfs(l + r >> 1, r));
return r - l;
}
void solve(){
int n;
cin >> n;
for (int i = 0; i < n; i ++ ) cin >> a[i];
int ans = dfs(0, n);
cout << ans << endl;
}
int main(){
int t; for (cin >> t; t -- ;) solve();
return 0;
}