func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long mod = 1e9 + 7;   const long long INF = 4e18;   const int inf = 2e9;   int gcd(int a, int b) { return b ? gcd(b, a % b) : a; }   int lcm(int a, int b) { return a * b / gcd(a, b); }   int a[3005], pos[3005];   int main(void) {     int n, i, j, naik = 0;     scanf( %d , &n);     for (i = 1; i <= n; ++i) {       scanf( %d , a + i);       pos[a[i]] = i;     }     int ans = 0;     for (i = 1; i <= n; ++i) {       while (pos[i] > i) {         swap(a[pos[i]], a[pos[i] - 1]);         swap(pos[a[pos[i]]], pos[a[pos[i] - 1]]);         ans++;       }     }     ans = ((ans >> 1) << 2) + (ans & 1);     printf( %.9f n , (double)ans);     return 0;   }   