HackerRank SDE Intern Interview Experience | Bangalore | Chakra AI Interviewer

Interview Experience: Software Development Engineer (SDE) Intern

Location: Bangalore (Onsite)

Interviewer: Chakra AI Interviewer

Overall Experience: The interview went very smoothly. The AI interviewer was clear with instructions, and the overall flow felt structured and interactive.

Interview Structure

The interview consisted of 1 core DSA problem followed by a series of logical follow‑up questions and edge‑case discussions based on the written code.

---

The DSA Problem: Password Strength Checker

Input:

List<String> passwords — A list of password strings to evaluate.
List<String> common_words — A list of common or dictionary words that shouldn't appear in strong passwords.

Output:

List<String> — A list containing "weak" or "strong" corresponding to each password in the input list.

Rules for a Weak Password: A password is classified as weak if it satisfies any of the following conditions:

• Uniform Character Type: It consists entirely of numbers, entirely of lowercase letters (a‑z), or entirely of uppercase letters (A‑Z).
• Blacklisted Words: It contains any word from common_words as a substring.
• Length Constraint: Its length is less than 6 (len < 6).

Otherwise, the password is considered strong.

Approach & Solution Strategy

• Iteration & Validation: For each password in the passwords list, run through validation checks:
  • Length check: If password.length() < 6, mark as "weak".
  • Character type check: Track flags for containing digits, lowercase letters, and uppercase letters to see if it belongs to only a single category.
  • Common words check: Check if any word from the common_words collection is present within the password string.
• Result Compilation: Append "weak" or "strong" to the result list based on the evaluation flags.

---

Follow‑Up Questions

1. Preprocessing for Single String Check:

   • Question: What if instead of a list of passwords, you are given a single continuous string password, and you need to check it against a large dictionary of common words? What preprocessing would you perform?
   • Discussion: Discussed using a Trie data structure for efficient multi‑pattern string matching instead of checking substrings linearly or we can use hashing too.

2. Code Modification & Verification: The interviewer made minor tweaks directly to the logic and asked to trace whether the code would still produce correct outputs or if edge cases would break it.

3. Edge Case Analysis: Tested scenarios with empty strings, passwords containing special characters alongside uniform letters, and overlapping common words.