Bloomberg interview questions

What project are you most proud of?

Companies: Bloomberg, Adyen, Amazon, Anthropic +37

Last reported Jan 2025

3Sum

Find all unique triplets in an integer array that sum to zero, ensuring no duplicate triplets in the output. The core challenge is efficiently enumerating…

Companies: Bloomberg, Amazon, Apple, Google +5

Array · Sorting · Two Pointers

3Sum Closest

Given an integer array and a target, find three numbers whose sum is closest to the target (unique solution guaranteed) and return that sum. This…

Companies: Bloomberg

Array · Sorting · Two Pointers

Add Two Numbers

Companies: Bloomberg, Amazon, Google, Meta +2

Linked List · Math · Recursion

Best Time to Buy and Sell Stock

Given an array of daily stock prices, compute the maximum profit achievable from exactly one buy-before-sell transaction (i.e., the largest prices[j] - prices[i] with j…

Companies: Bloomberg, Adobe, Amazon, Apple +10

Array · Dynamic Programming

Best Time to Buy and Sell Stock II

Given daily stock prices, compute the maximum profit you can achieve with unlimited buy/sell operations while holding at most one share at a time (you…

Companies: Bloomberg, Apple, Meta, Oracle

Array · Dynamic Programming · Greedy

Binary Search

Given a sorted (ascending) array of unique integers and a target value, return the index of the target or -1 if not present; the solution…

Companies: Bloomberg, Amazon, Google, Meta +1

Array · Binary Search

Bus Routes

Given repeating bus routes and start/target stops, find the minimum number of bus rides required to go from source to target (or -1 if impossible)…

Companies: Bloomberg, Amazon, Coupang, PayPal +3

Array · Breadth-First Search · Hash Table

Climbing Stairs

Count the number of distinct sequences of 1- or 2-step moves that sum to n — the ways follow the recurrence ways(n)=ways(n-1)+ways(n-2) (i.e., Fibonacci-like), with…

Companies: Bloomberg, Google, Intuit, Meta +1

Dynamic Programming · Math · Memoization

Concatenation of Array

Given an integer array nums, produce ans by concatenating nums with itself so that ans has length 2n and ans[i]=nums[i], ans[i+n]=nums[i] for 0<=i<n; this is…

Companies: Bloomberg, Google

Array · Simulation

Container With Most Water

Given heights of vertical lines at unit-spaced x-coordinates, pick two indices i<j to maximize the area min(height[i],height[j])*(j-i). With n up to 1e5, the problem requires…

Companies: Bloomberg, Amazon, Cisco, Flipkart +4

Array · Greedy · Two Pointers

Customer Who Visited but Did Not Make Any Transactions

Given Visits and Transactions tables, identify customers who had visits with no matching transaction records and return each customer_id with the count of such no-transaction…

Companies: Bloomberg

Database

Design a price alert system

Matching price streams against millions of thresholds: ordered evaluation, hot-instrument fanout, and reliable one-shot notifications.

Companies: Bloomberg, Coinbase, Meta, Swyftx +1

event-ordering · hot-keys · idempotency · notification-delivery

Design a real-time stock price feed

Global latest-value streaming: source ordering, hot-symbol fanout, conflation, and reconnecting through lagging regions without rolling prices backward.

Companies: Bloomberg, Amazon, Google

backpressure · fanout · ordering · pub-sub

Design a top K trending system

Continuously changing rankings: sliding-window expiration, exact distributed top K, viral articles, and share-ID deduplication across delivery and replay.

Companies: Bloomberg, Amazon, LinkedIn, Meta +2

deduplication · distributed-top-k · event-time · hot-keys

Find the Index of the First Occurrence in a String

Given two strings, return the starting index of the first occurrence of needle in haystack, or -1 if absent. This is a classic substring search…

Companies: Bloomberg, Google, Meta, Microsoft

Boyer–Moore String-Search Algorithm · Knuth–Morris–Pratt Algorithm · String · String Matching

Generate Parentheses

Given a number n, generate all distinct well-formed parentheses strings formed from n pairs of opening and closing brackets. Return all valid combinations as a…

Companies: Bloomberg, Amazon, Microsoft, Salesforce

Backtracking · Bracket Sequences · Dynamic Programming · String

Group Anagrams

Group the input strings into lists of anagrams — i.e., strings that contain the same multiset of letters — and return the groups in any…

Companies: Bloomberg, Amazon, Apple, Arize Ai +14

Array · Hash Table · Sorting · String

Koko Eating Bananas

Find the minimum integer eating speed k such that the total hours required (sum over piles of ceil(piles[i]/k)) is ≤ h; because the required hours…

Companies: Bloomberg, Amazon, Coupang, DoorDash +6

Array · Binary Search

Kth Largest Element in an Array

Return the k-th largest element (by sorted order, not distinct) from an unsorted array. For inputs up to ~1e5 elements, solve it faster than full…

Companies: Bloomberg, LinkedIn, Meta, Salesforce +1

Array · Divide and Conquer · Heap (Priority Queue) · Quickselect

Largest Rectangle in Histogram

Find the maximum area of a rectangle formed by contiguous bars in a histogram (given bar heights). The core challenge is determining each bar's maximal…

Companies: Bloomberg, Microsoft

Array · Monotonic Stack · Range Minimum/Maximum Query · Stack

Longest Common Prefix

Return the longest prefix string common to all strings in the array, or an empty string if none exists. The task reduces to comparing characters…

Companies: Bloomberg, Amazon, Apple, Google +3

Array · String · Trie