Free AI LeetCode Communication Coach — Group Anagrams

The problem

Given an array of strings, group the anagrams together. You can return the answer in any order.

Example: strs = ["eat","tea","tan","ate","nat","bat"] → [["eat","tea","ate"],["tan","nat"],["bat"]]

Name the signature, then one bucket example.

from collections import defaultdict
groups = defaultdict(list)
for w in strs:
    groups["".join(sorted(w))].append(w)
return list(groups.values())

How to explain it

1. 1. Restate

   Say the problem in your own words.

   One or two sentences. Show you understood the input, the output, and the goal — not that you memorised the prompt.

2. 2. Approach

   Name the method before you code.

   Brute force first if you need it, then the structure you will use: hash map, two pointers, stack, binary search.

3. 3. Example

   Walk one concrete input.

   Pick small numbers. Say what you store, what you compare, and what you return. Interviewers follow an example more easily than abstract talk.

4. 4. Time and space

   One sentence each.

   After the example, before you claim you are done. “Time is O(n) because we scan once. Space is O(n) for the map.”

5. 5. Edge cases

   Name at least one unusual input.

   Empty input, duplicates, already sorted, overflow. Invite a follow-up: “I would also check …”

• “I will key the map by a signature.”
• “Sorting the letters gives a stable key for anagrams.”

Practise out loud

1. 1. Restate

   I need to group words that are anagrams of each other — same letters, different order.

2. 2. Approach

   I will build a hash map from a signature to a list. The signature can be the sorted letters of the word.

3. 3. Example

   For eat, tea, ate — sorting gives aet, so they share one bucket. tan and nat share ant. bat is alone.

4. 4. Time and space

   Time is O(n times k log k) if I sort each word of length k. Space is O(n k) for the map.

5. 5. Edge cases

   I would check an empty input and words of length one.

Common mistakes when explaining Group Anagrams

• Not naming the signature key clearly.
• Skipping an example bucket walkthrough.
• Claiming O(n) when each sort costs k log k.