func_code_string: #include <bits/stdc++.h>   using namespace std;   #define fast ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);   int main()   {       fast;       int t;       cin >> t;       while (t--)       {           int n;           cin >> n;           vector<int> a(n + 1);           a[0] = 0;           for (int i = 1; i <= n; i++)               a[i] = i;           if (n % 2 == 0)           {               for (int i = 1; i < n; i += 2)                   swap(a[i], a[i + 1]);           }           else           {               for (int i = 1; i < n - 2; i+= 2)                   swap(a[i], a[i + 1]);               int temp = a[n];               a[n] = a[n - 1];               a[n - 1] = a[n - 2];               a[n - 2] = temp;           }           for (int i = 1; i <= n; i++)               cout << a[i] <<    ;           cout << endl;       }   }