func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxn = 4e5 + 4;   const int oo = 1e8 + 7;   int n, a[maxn], cc, p;   long long s[maxn];   int main() {     cin >> n;     a[1] = 1;     a[2] = 2 * n;     a[n + 1] = 2;     a[n + 2] = 2 * n - 1;     int cc = 3;     for (int i = 3; i <= (n); ++i) {       if (i % 2) {         a[i] = cc;         a[i + n] = cc + 1;         cc += 2;       } else {         a[i + n] = cc;         a[i] = cc + 1;         cc += 2;       }     }     long long k = 0;     for (int i = 1; i <= (2 * n); ++i) k += i;     for (int i = 2 * n + 1; i <= (4 * n); ++i) a[i] = a[i - 2 * n];     for (int i = 1; i <= (4 * n); ++i) s[i] = s[i - 1] + a[i];     k = k / 2;     k++;     for (int i = 1; i <= (3 * n); ++i) {       long long x = s[i + n - 1] - s[i - 1];       if (abs(x - k) > 1) {         cout <<  NO ;         return 0;       }     }     cout <<  YES n ;     for (int i = 1; i <= (2 * n); ++i) cout << a[i] <<    ;   }   