Bloomberg Coding Interview Questions
32 Bloomberg coding interview problems with full optimal solutions — 16 easy, 13 medium, 3 hard. Every problem ships with multiple approaches (brute-force first, then the optimal), complexity tables for each, company-specific tips on what an Bloomberg interviewer values, and a FAQ section.
Showing 16 problems of 32
- #217easyfoundational
217. Contains Duplicate
Bloomberg's data-ingestion pipelines must flag duplicate trade confirmations before they corrupt position ledgers — this warmup problem tests whether you instinctively reach for a hash set instead of nested loops when deduplication speed matters.
- #412easyfoundational
412. Fizz Buzz
Bloomberg uses Fizz Buzz as a pure communication test — they want to hear you enumerate edge cases aloud (divisible by both 3 and 5 first), mirroring how Bloomberg engineers articulate business-rule precedence before touching a trading system's branching logic.
- #1easyfoundational
1. Two Sum
Two Sum is the canonical Bloomberg warm-up: return the indices of two numbers in an array that add to a given target. Bloomberg uses it on phone screens to gauge whether you can narrate the space-for-time tradeoff before reaching for the optimal one-pass hash map.
3 free resourcesSolve → - #9easyfrequently asked
9. Palindrome Number
Given an integer x, return true if x is palindrome. Bloomberg uses this as a follow-up to Reverse Integer — they want to see the without-converting-to-string optimization to test whether you can think about numeric problems numerically.
3 free resourcesSolve → - #13easyfoundational
13. Roman to Integer
Convert a Roman-numeral string to an integer. Bloomberg uses this to test whether you can handle the subtractive notation (IV, IX, XL, XC, CD, CM) elegantly — the obvious solution has six special cases, the elegant one has none.
3 free resourcesSolve → - #14easyfrequently asked
14. Longest Common Prefix
Find the longest common prefix shared by an array of strings. Bloomberg uses this as a string-iteration test — they want clean code that handles the empty-input edge and discusses vertical vs horizontal scan tradeoffs.
3 free resourcesSolve → - #20easyfoundational
20. Valid Parentheses
Given a string containing only the characters '(', ')', '{', '}', '[' and ']', determine if it is balanced. Bloomberg asks this as a stack-fluency check: can you spot the data structure without prompting and implement it correctly on the first try.
3 free resourcesSolve → - #21easyfoundational
21. Merge Two Sorted Lists
Splice two ascending linked lists into one sorted list. Bloomberg uses this to test pointer hygiene and the dummy-head trick — they want clean code with no special-case branching for the empty-list edge.
3 free resourcesSolve → - #28easyfrequently asked
28. Find the Index of the First Occurrence in a String
Implement strStr() — return the index of the first occurrence of needle in haystack, or -1. Bloomberg uses this as the gateway to substring algorithms: brute force is fine for warm-up, but they always probe for KMP if the conversation goes deeper.
3 free resourcesSolve → - #121easycompany favorite
121. Best Time to Buy and Sell Stock
Given a daily price series, return the maximum profit from one buy + one sell. Bloomberg leans on this for finance-engineering candidates — it's a single-pass greedy that mirrors the real-world 'running max profit' calculation traders care about.
3 free resourcesSolve → - #125easyfrequently asked
125. Valid Palindrome
Given a string, determine if it's a palindrome after removing non-alphanumeric characters and ignoring case. Bloomberg uses this to test two-pointer fluency plus a careful handling of mixed-content strings.
3 free resourcesSolve → - #136easyfrequently asked
136. Single Number
Every element appears twice except one. Find the one. Bloomberg uses this to test the XOR trick — they want the linear-time, constant-space solution, not the hash-set fallback.
3 free resourcesSolve → - #168easyfrequently asked
168. Excel Sheet Column Title
Convert a positive integer to its Excel-style column title (A, B, ..., Z, AA, AB, ...). Bloomberg uses this to test whether you can handle a base-26 conversion with the 1-indexed twist that breaks standard base-conversion code.
3 free resourcesSolve → - #206easyfoundational
206. Reverse Linked List
Reverse a singly linked list. Bloomberg uses this as a linked-list fluency check — they want to see both the iterative pointer-rewire and the recursive version, plus an articulate reason for picking one over the other.
3 free resourcesSolve → - #268easyfrequently asked
268. Missing Number
An array of n distinct numbers in [0, n] is missing one. Find it. Bloomberg uses this to test whether you know multiple O(n)/O(1) tricks — sum formula AND XOR fold — and can pick between them based on the input constraints.
3 free resourcesSolve → - #387easyfrequently asked
387. First Unique Character in a String
Given a string, find the index of the first non-repeating character, or -1 if all repeat. Bloomberg uses this as a hash-map fluency warm-up — they want a two-pass O(n) with a discussion of LinkedHashMap (or ordered Map) as an alternative.
3 free resourcesSolve →
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