Oracle Software Developer interview questions

Round 1(Coder Pad & Zoom): The interviewer had a look at my resume and asked about my current project and technology stack that I am familiar with. After that, she asked me to solve a coding problem. Question 1: Given an array of Integers which is the level order traversal of a binary tree, And asked me to find out whether it is a binary search tree or not. Question 2: Given a string containing Integers. Find the number of ways in which we can decode the string into upper case English alphabets. Assume 'A' stands for 1 and 'B' stands for 2 …..'Z' stands for 26. (Practice Link) I have implemented using recursion and dynamic programming (to avoid re-computing the same sub-problems). She tested the code with some test cases and edge cases as well and asked me the complexity of the program if I haven't used dynamic programming. I answered it as O(2^n). She said that this was the last question in this round and wished me the best of luck for the second round which will start in 15 mins. Round 2(Coder Pad & Zoom): The interviewer asked about my current project and the tech stack that I am using. Then he asked some question on core Java which are as follows Why we use gateway's in Microservices Significance of volatile keyword After me answering these questions, he gave me some coding problems which are as follows Question 1:Given an array write a program to detect duplicates.