Most Common Word
A easy-tier problem at 45% community acceptance, tagged with Array, Hash Table, String. Reported in interviews at Datadog and 0 others.
Most Common Word shows up on Datadog's assessments and looks deceptively simple: find the most frequently occurring word in a list, excluding a set of banned words. The 44% acceptance rate tells you people are stumbling on edge cases and implementation details, not the core idea. You'll need to count word frequencies and handle filtering correctly, which sounds trivial until you're live and realize you forgot to normalize capitalization or strip punctuation. If you blank on the implementation during the OA, StealthCoder surfaces a working solution in seconds while the proctor sees nothing.
Companies that ask "Most Common Word"
Most Common Word is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Made by an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too.
Get StealthCoderThe trap here is assuming the problem is just hash table counting. It is, but only after you handle preprocessing. Most candidates either skip lowercasing entirely, forget to filter banned words from the banned list (not just the input), or miscalculate the tie-breaker when multiple words share max frequency. The algorithmic flow is straightforward: normalize strings, filter banned entries, count frequencies using a hash table, find the max. What kills submissions is sloppy string handling and not testing against words that appear the same number of times. This is a warm-up problem that punishes careless implementations. When you hit it under time pressure in an assessment and the parsing logic trips you up, StealthCoder gives you the correct approach without the friction.
Pattern tags
You know the problem.
Make sure you actually pass it.
Most Common Word recycles across companies for a reason. It's easy-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Made by an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Most Common Word interview FAQ
What does the 44% acceptance rate mean for this problem?+
Below 50% suggests most failures aren't from not knowing what a hash table is. Candidates are losing points to edge cases: capitalization, punctuation, ties in frequency, or mishandling the banned word list. Test your string normalization thoroughly.
Is Most Common Word still asked at real companies?+
Datadog has asked it. It's a canonical warm-up or screening problem at many companies. Don't skip it assuming it's too basic. The simplicity of the task masks the detail work required to pass all test cases.
What's the core algorithmic trick?+
There isn't one. It's pure execution: normalize input (lowercase, strip punctuation), filter banned words, populate a hash table with counts, return the key with max value. The trick is doing each step correctly under pressure.
How does this relate to the Hash Table and Counting topics?+
Hash tables are the data structure for storing word frequencies in O(1) lookup. Counting is the whole problem: iterate once to tally, iterate the table once to find max. Both are foundational patterns you'll see in harder problems.
What should I test before submitting?+
Edge cases: words with punctuation, uppercase vs. lowercase, all words banned except one, empty input after filtering, and ties in frequency. Run through at least three examples on paper first.
Want the actual problem statement? View "Most Common Word" on LeetCode →