**Update: Moving on to the Final round**\n\nI applied for Google Software Engineering III role back in November and a recuiter got back to me to schedule first round. I have 2.5 YOE. I had two telephonic rounds. In the first one, I got recommended for L3 but my recruiter wanted me to give another and get recommended for L4. \n\n\n```\nQuestion:\nYou\u2019re given a string which may contain "bad pairs".\nA bad pair is defined as a pair of adjacent characters, where they are the same letter in different cases. For example, "xX" is a bad pair, but "xx" or "XX" are not.\nImplement a solution to remove the bad pairs from the string.\nSample:\n\t\u2022 Input: abxXw\n\t\u2022 Output: abw\nAdditional Case:\nIf the input string is empty:\n\t\u2022 Input: ""\n\t\u2022 Output: ""\n\nI used stack to solve the question.\n\nFollowups\n1. Can you write some unit test cases for your solution. Think it as if you are designing a feature. What unit test cases will I consider?\nI gave some couple of unit test cases and he was fine with it\n\n2. How will I solve it without using stack and give me a dry test run?\nMy response: I used 2 pointers approach gave him some dry test run.\n\nI\'m still waiting for feedback. \n```

Update: Moving on to the Final round\n\nI applied for Google Software Engineering III role back in November and a recuiter got back to me to schedule first roun