Problem database last updated: June 20, 2025
13 problems · 2 Easy, 7 Medium, 4 Hard · Ranked #121 of 458
2 Easy
15% · avg 23%
7 Medium
54% · avg 59%
4 Hard
31% · avg 18%
Based on 13 reported problems, Twilio interviews are significantly harder than average - 31% Hard vs 18% across all companies. The majority (54%) of questions are Medium difficulty, which is typical for companies that want to see solid fundamentals without excessive trick questions.
Compared to the industry average, Twilio puts unusual emphasis on greedy (30.8% of problems, 3.6x the industry average), heap-priority-queue (15.4% of problems, 2.5x the industry average), sorting (30.8% of problems, 2.1x the industry average). If you're short on time, these are the categories to double down on.
The most common topics are array (61.5%), string (53.8%), greedy (30.8%), sorting (30.8%). Problems below are sorted by frequency, the ones at the top are asked most often.
| Problem | Difficulty | Frequency | Topics | |
|---|---|---|---|---|
Maximize Greatness of an Array You are given a 0-indexed integer array nums. You are allowed to permute nums into a new array perm of your choosing. | Medium | Very Likely | arraytwo-pointersgreedy | Solve |
Univalued Binary Tree A binary tree is uni-valued if every node in the tree has the same value. | Easy | Very Likely | treedepth-first-searchbreadth-first-search | Solve |
Reformat Date Given a date string in the form Day Month Year, where: | Easy | Very Likely | string | Solve |
Top K Frequent Elements Given an integer array nums and an integer k, return the k most frequent elements. You may return the answer in any order. | Medium | Likely | arrayhash-tabledivide-and-conquer | Solve |
Letter Combinations of a Phone Number Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent. Return the answer in any order. | Medium | Likely | hash-tablestringbacktracking | Solve |
Reconstruct Itinerary You are given a list of airline tickets where tickets[i] = [fromi, toi] represent the departure and the arrival airports of one flight. Reconstruct the itinerar... | Hard | Likely | arraystringdepth-first-search | Solve |
Minimum Equal Sum of Two Arrays After Replacing Zeros You are given two arrays nums1 and nums2 consisting of positive integers. | Medium | Likely | arraygreedy | Solve |
Ways to Make a Fair Array You are given an integer array nums. You can choose exactly one index (0-indexed) and remove the element. Notice that the index of the elements may change after... | Medium | Likely | arrayprefix-sum | Solve |
Minimum Number of Swaps to Make the String Balanced You are given a 0-indexed string s of even length n. The string consists of exactly n / 2 opening brackets '[' and n / 2 closing brackets ']'. | Medium | Likely | two-pointersstringstack | Solve |
First Missing Positive Given an unsorted integer array nums. Return the smallest positive integer that is not present in nums. | Hard | Likely | arrayhash-table | Solve |
Group Anagrams Given an array of strings strs, group the anagrams together. You can return the answer in any order. | Medium | Likely | arrayhash-tablestring | Solve |
Wildcard Matching Given an input string (s) and a pattern (p), implement wildcard pattern matching with support for '?' and '' where: | Hard | Likely | stringdynamic-programminggreedy | Solve |
Text Justification Given an array of strings words and a width maxWidth, format the text such that each line has exactly maxWidth characters and is fully (left and right) justifie... | Hard | Likely | arraystringsimulation | Solve |
Maximize Greatness of an Array
SolveYou are given a 0-indexed integer array nums. You are allowed to permute nums into a new array perm of your choosing.
Univalued Binary Tree
SolveA binary tree is uni-valued if every node in the tree has the same value.
Top K Frequent Elements
SolveGiven an integer array nums and an integer k, return the k most frequent elements. You may return the answer in any order.
Letter Combinations of a Phone Number
SolveGiven a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent. Return the answer in any order.
Reconstruct Itinerary
SolveYou are given a list of airline tickets where tickets[i] = [fromi, toi] represent the departure and the arrival airports of one flight. Reconstruct the itinerar...
Minimum Equal Sum of Two Arrays After Replacing Zeros
SolveYou are given two arrays nums1 and nums2 consisting of positive integers.
Ways to Make a Fair Array
SolveYou are given an integer array nums. You can choose exactly one index (0-indexed) and remove the element. Notice that the index of the elements may change after...
Minimum Number of Swaps to Make the String Balanced
SolveYou are given a 0-indexed string s of even length n. The string consists of exactly n / 2 opening brackets '[' and n / 2 closing brackets ']'.
First Missing Positive
SolveGiven an unsorted integer array nums. Return the smallest positive integer that is not present in nums.
Group Anagrams
SolveGiven an array of strings strs, group the anagrams together. You can return the answer in any order.
Wildcard Matching
SolveGiven an input string (s) and a pattern (p), implement wildcard pattern matching with support for '?' and '' where:
Text Justification
SolveGiven an array of strings words and a width maxWidth, format the text such that each line has exactly maxWidth characters and is fully (left and right) justifie...
Frequency scores are based on crowdsourced interview reports. A higher score means the problem has been reported more often in recent Twilio interviews.
Very Likely
75-100%
Likely
50-74%
Sometimes
25-49%
Rare
0-24%
Twilio interviews focus heavily on array, string, greedy problems. If you're short on time, these are the categories to prioritize. The problems on this page are sorted by frequency, so start from the top and work your way down.
Beyond solving problems, practice explaining your approach. Twilio interviewers care about your thought process - how you break down a problem, consider edge cases, and evaluate tradeoffs between solutions. A clean O(n) solution you can explain clearly beats an O(log n) solution you can't articulate.
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Twilio has been reported to ask 13 distinct coding problems. The most common topics are array, string, greedy. 2 are Easy difficulty, 7 are Medium, and 4 are Hard. Problems are sorted by frequency - the ones at the top are asked most often.
Based on 13 reported problems, Twilio interviews are significantly harder than average - 31% Hard vs 18% across all companies. 54% of questions are Medium difficulty. Focus on the high-frequency Medium problems first, then work through the Hard ones.
Start with the highest-frequency problems listed on this page. Focus on the core topics: array, string, greedy. Practice solving them under time pressure and explaining your approach out loud. Mock interviews with AI can simulate the real experience.
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