Bloomberg interview questions

Majority Element

Given an array of n integers, return the element that appears more than ⌊n/2⌋ times (the majority element is guaranteed to exist). The goal is…

Companies: Bloomberg, Amazon, Coupang, Google +1

Array · Boyer–Moore Majority Vote Algorithm · Counting · Divide and Conquer

Median of Two Sorted Arrays

Find the median of two sorted arrays in O(log(m+n)) time by using binary search to partition the arrays so the left half contains the correct…

Companies: Bloomberg, Amazon, eBay, Goldman Sachs +5

Array · Binary Search · Divide and Conquer

Merge Sorted Array

Given two sorted arrays nums1 and nums2 and counts m and n (nums1 has length m+n with its last n slots free), merge the elements…

Companies: Bloomberg, Amazon, Google, Meta +2

Array · Sorting · Two Pointers

Minimum Insertions to Balance a Parentheses String

Given a string of '(' and ')', return the minimum number of insertions needed to make it balanced under the rule that each '(' must…

Companies: Bloomberg, Meta

Bracket Sequences · Greedy · Stack · String

Minimum Operations to Reduce X to Zero

Remove elements from either end to make the sum of removed elements equal x; equivalently, find the longest contiguous subarray whose sum equals total(nums) -…

Companies: Bloomberg

Array · Binary Search · Hash Table · Prefix Sum

Minimum Size Subarray Sum

Find the length of the shortest contiguous subarray of positive integers whose sum is at least a given target (return 0 if none exists). This…

Companies: Bloomberg, Meta, Toast

Array · Binary Search · Prefix Sum · Sliding Window

Next Permutation

Rearrange the array in-place to produce the lexicographically next greater permutation (using only O(1) extra space); if no larger permutation exists, reorder it to the…

Companies: Bloomberg, Amazon, Meta, Microsoft

Array · Two Pointers

Palindrome Number

Determine whether an integer's digit sequence reads the same forwards and backwards (return false for negative numbers); the follow-up asks to do this without converting…

Companies: Bloomberg, Amazon, Google, Meta +1

Math

Pascal's Triangle

Generate the first numRows of Pascal's Triangle as a list of lists, where each row starts and ends with 1 and every interior element equals…

Companies: Bloomberg

Array · Dynamic Programming

Remove Duplicates from Sorted Array

Given a sorted array, remove duplicates in-place so each unique value appears only once (preserving order) and return the count k of unique elements. This…

Companies: Bloomberg, Google, Meta, Microsoft

Array · Two Pointers

Reverse Integer

Reverse the digits of a signed 32-bit integer, preserving the sign, and return the reversed number or 0 if reversing would overflow the 32-bit signed…

Companies: Bloomberg, eBay, Google, Meta +2

Math

Reverse Linked List II

Companies: Bloomberg, Apple

Linked List

Rotate Image

Given an n×n matrix, rotate it 90° clockwise in-place (no extra matrix allowed), i.e., rearrange the elements so each row becomes the corresponding column after…

Companies: Bloomberg, ByteDance, Meta, NVIDIA

Array · Math · Matrix

Search Insert Position

Given a sorted array of distinct integers and a target, return the index where the target is found or the index where it should be…

Companies: Bloomberg, Google, Grammarly, Meta

Array · Binary Search

Single Number

Given an array where every element appears exactly twice except for one, return the element that appears only once. Achieve O(n) time and O(1) space…

Companies: Bloomberg, Amazon, Meta

Array · Bit Manipulation

Sliding Window Maximum

Given an integer array and a window size k, return the maximum value for each contiguous subarray (sliding window) as it moves one step to…

Companies: Bloomberg, Amazon, D. E. Shaw, Expedia +7

Array · Heap (Priority Queue) · Monotonic Queue · Queue

Squares of a Sorted Array

Given an integer array sorted in non-decreasing order (which may contain negative numbers), return a new array of the squares of each number, also sorted…

Companies: Bloomberg, Instacart, Uber

Array · Sorting · Two Pointers

Subarray Sum Equals K

Count the number of contiguous, non-empty subarrays whose elements sum to k. Because nums can include negatives (so two-pointer sliding window doesn't work), use cumulative…

Companies: Bloomberg, Amazon, Apple, Google +3

Array · Hash Table · Prefix Sum

Sum of Squares of Special Elements

Given a 1-indexed integer array nums of length n, compute the sum of squares of all elements at indices i that divide n (i.e., n…

Companies: Bloomberg

Array · Enumeration

Top K Frequent Elements

Given an integer array and k, return the k most frequent elements — the core challenge is to count element frequencies and extract the top-k…

Companies: Bloomberg, Amazon, Google, Meta +9

Array · Bucket Sort · Counting · Divide and Conquer

Two Sum

Given an array of integers and a target, return the indices of two distinct elements whose values sum to the target (exactly one valid solution…

Companies: Bloomberg, Amazon, Apple, Brex +13

Array · Hash Table

Using a Robot to Print the Lexicographically Smallest String

Given a string s and an empty buffer t that acts like a stack (you can push s's first char onto t or pop t's…

Companies: Bloomberg, Expedia, Rippling

Greedy · Hash Table · Stack · String