Bloomberg Software Engineer interview questions

Applied through online application, got an phone-interview 3 weeks later. The phone interview did not involve coding, just asked me to explain two algorithm questions. 1.Given two stack classes, how to implement a queue with dequeue and enqueue operation both with O(1) time complexity. 2.Find the longest palindrome in a string. Just keep asking me if I could give faster solution. I end up giving a O(n^2) solution.

Two engineers. They asked questions one by one. The first question is to design a structure for the emplyee/manager system. An employee belongs to a manager. A manager has several employees. They may also belong to a manager. Design the structure so that it supports the following operation: delete an employee/manager, promotion(an employee becomes a manager). The second question is level-traversal a binary tree. The third one is about pass by reference or pass by value.