Given an org chart tree, compute each employee's level, identify balanced employees, and build a histogram of employees by level.

Focus on understanding the structure of the org chart tree and how to traverse it effectively, likely using depth-first or breadth-first search algorithms. Clearly define what constitutes a "balanced" employee—typically, this refers to employees who have the same number of direct reports across their subordinates. When building the histogram, ensure you can efficiently count the number of employees at each level and represent this data clearly. Be prepared to discuss edge cases, such as handling employees with no subordinates or varying tree depths, and consider the time and space complexity of your solution.