I applied online. The process took 3 months. I interviewed at TikTok (Mountain View, CA) in Oct 2021
Interview
This was for New Grad position. Applied late September and received OA invite a week later. OA had a prescheduled window of two days to complete. After completing OA, received first technical round invite a month later. Received invite to second technical round a day after first round and then HM round a day after the second technical (all rounds about 2 weeks apart). Two days after HM, invited to call with HR and received offer.
Round 1: HackerRank OA, 5 questions in 120 minutes
Round 2: Technical Interview
Round 3: Technical Interview
Round 4: Interview with Hiring Manager
Overall the interviewers were all very polite throughout the interview and helpful when answering questions, which seems to be out of the norm based on the other interviews listed on this site, though all my interviewers were US based, which may have made the difference.
Interview questions [1]
Question 1
OA: 2 easy, 2 medium, 1 hard
Technical 1: Medium graph then hard follow-up
Technical 2: Medium geometric (basic geometry though), then questions related to the team I would be on
HM: Medium tree, interviewer indicated there would be followup but ran out of time doing the first medium
OA - 1 arrays Medium, 1 Trie Hard. I had 45 minutes to complete that. I was able to do the medium in about 15-20 minutes but I am not that great with trie ds so I was not able to finish.
Four Round Process
Phone Interview with Human Resources
Coding Round; 1 DSA Leetcode Medium Q
Coding Round: 2 DSA Leetcode Medium Q
Manager Round: System Design Q and behavioural Q
It took about four weeks from application to offer, longer than I initially expected. The initial phone screen was straightforward, covering my resume and some basic algorithms. Then came the technical rounds, which were challenging. One question on minimum window substrings had me diving into a sliding-window approach using pointers and hashmaps. Funny enough, I recognized it mid-round as something I’d practiced on PracHub just days before. After a final system design discussion, I received the offer and happily accepted.
Interview questions [1]
Question 1
Given two strings s and t, return the minimum window substring of s that contains every character of t including duplicates, or an empty string if no such window exists. Walk through the sliding-window approach using two pointers and a character-frequency hashmap, analyze the O(|s| + |t|) time complexity, and discuss how to adapt it when t contains characters not present in s or when s arrives as a stream that cannot be fully buffered.