Find the Pivot Integer Problem & Solution

#pragma GCC optimize("Ofast")
#pragma GCC optimization("unroll-loops")

static const int _=[](){ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);return 0;}();

class Solution {
public:
  int pivotInteger(int n) {
    int total = n * (n + 1) / 2;
    for (int i = 1; i <= n; ++i) {
      int left = i * (i + 1) / 2;
      int right = total - left + i;
      
      if (left == right) {
        return i;
      }
    }

    return -1;
  }
};