func_code_string: #include <bits/stdc++.h>   const double pi = acos(-1.0);   const int maxn = (5e2 + 10);   const int inf = 0x3f3f3f3f;   const long long mod = 1e9 + 7;   using namespace std;   map<long long, long long> ys;   long long a[200010];   int main() {     cin.tie(0);     ios::sync_with_stdio(false);     long long n;     long double ans = 0, sum = 0;     cin >> n;     for (long long i = 1; i <= n; i++) {       cin >> a[i];       sum += a[i];       ys[a[i]] += 1;     }     for (long long i = 1; i <= n; i++) {       ans += sum - (long double)(n - i + 1) * (long double)a[i];       ans += ys[a[i] - 1] - ys[a[i] + 1];       sum -= a[i];       ys[a[i]] -= 1;     }     cout << fixed << setprecision(0) << ans;     return 0;   }   