func_code_string: #include <bits/stdc++.h>   using namespace std;   long double dp[9000001] = {};   bool vis[9000001] = {};   long double solve(int inv) {     if (inv == 0) return 0;     if (inv == 1) return 1;     if (vis[inv]) return dp[inv];     vis[inv] = 1;     return dp[inv] = 4 + solve(inv - 2);   }   int main() {     std::ios::sync_with_stdio(false);     int n;     cin >> n;     std::vector<int> v(n);     for (int i = 0; i < n; i++) cin >> v[i];     int inv = 0;     for (int i = 0; i < n; i++) {       for (int j = i + 1; j < n; j++)         if (v[j] < v[i]) inv++;     }     cout << fixed << setprecision(9) << solve(inv);   }   