I applied online. The process took 2 weeks. I interviewed at TikTok (Singapore) in Mar 2023
Interview
HR screening and call, followed by 3 rounds, which are usually deep dive into past projects/work and Leetcode questions, although there may be system design as well. There is then one last behavioral screening round. Some interviewers are friendly, others are just rude. Most of them prefer to interview in Mandarin, which makes explaining difficult if you are not proficient at the language, or be stuck in communicating with broken English.
Interview questions [1]
Question 1
Leetcode medium to hard, questions on binary search, stack (e.g. valid parenthesis string with wildcard), linked lists (e.g. LRU cache, merge K sorted), graphs (e.g. count islands) and DP (e.g. decode ways). Lots of grinding needed to be familiar with the algorithms as you have to answer 2-3 questions in each round so you have to be fast.
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.
