Amdocs interview questions

First round happened with third party careerfloteam, 1 hour long, mixed question of array, string manupulation,sql queries. Second round happened with development manager went for 1.5 hrs create a deadlock situation, write palindrome with all possible conditions, c++ all normal questions, Design pattern, factory and builder pattern difference. Third round happened with Isreal architects(3 people) went for more thn 2 hours, singleton design pattern, finding missing number in unsorted( duplicate number available) from int array, optimize it, complexity. Give questions in inheritance and polymorphism. Ask to implement shapes, Create Design for shapes, circle and picture(collection of shapes)