DSA: Topic 2: Hash Maps & Sets
Why interviewers ask hash map questions They want to see if you can: Trade a little extra memory for much faster runtime. Recognise repeated lookups. Avoid nested loops. A common interview progression is: Candidate writes O(n²) → Interviewer asks, "Can you optimise this?" → Expected answer: use a hash map. What is a Hash Map? In Python, a hash map is a dictionary . student = { " Alice " : 95 , "…
In this briefing, we discuss hash maps and sets, focusing on their applications in coding interviews. Hash maps, also known as dictionaries in Python, provide fast insertion, search, and deletion operations with an average time complexity of O(1). Sets, on the other hand, store unique elements and are useful when you only need to check for existence or remove duplicates.
The article highlights common interview patterns involving hash maps and sets, such as frequency counting and fast lookup problems. For frequency counting, an example provided is finding the most frequent number in a list, while for fast lookup, the example is checking if an array contains duplicates.
Brief written by urgent.news from Dev.to's own syndicated text. Machine-written — may contain errors; check the original before relying on it.
