Software Engineer Coding & Algorithms Interview Questions

Practice 2,743 real Coding & Algorithms interview questions for Software Engineer roles. From companies including Meta, Amazon, Google, Uber, Microsoft.

2.7k Questions 325 Companies08.16.2026
Showing 20 results
Role
Amazon logo
Amazon
Hard
Software Engineer

Minimize operations to reduce price difference

You are managing an inventory of products and want to adjust their prices. There are n products. The price of the i-th product is given by an integer ...

Coding & Algorithms
6
0
56 people solved
Oct 1, 2025
xAI logo
xAI
Medium
Software Engineer

Token Bucket Rate Limiter with Lazy Refill Backed by a Cache

Token Bucket Rate Limiter with Lazy Refill Backed by a Cache You are building the enforcement layer of a rate limiter. Every user has a token bucket s...

Coding & Algorithms
1
1
13 people solved
Sep 23, 2025
xAI logo
xAI
Medium
Software Engineer

Implement a Radix Cache for Integer Sequences

Implement a RadixCache — a radix tree (prefix-compressed trie) that stores sequences of integers. In a plain trie, every node holds exactly one elemen...

Coding & Algorithms
0
0
10 people solved
Sep 21, 2025
Two Sigma logo
Two Sigma
Medium
Software Engineer

All Subsequences After Deleting One Character

You are given a string s of length n consisting of lowercase English letters. Consider every string that can be obtained by deleting exactly one chara...

Coding & Algorithms
0
0
7 people solved
Sep 19, 2025
Two Sigma logo
Two Sigma
Medium
Software Engineer

Autoscale a Server Fleet from Throughput Readings

You run a service on a fleet of identical servers behind a load balancer. Each server can handle at most limit units of throughput. A monitoring syste...

Coding & Algorithms
0
0
5 people solved
Sep 19, 2025
Capital One logo
Capital One
Medium
Software Engineer

Count ordered pairs that concatenate to target

Given a list of integers numbers and an integer target, count the number of ordered pairs (i, j) with i != j such that concatenating numbers[i] follow...

Coding & Algorithms
15
0
109 people solved
Sep 19, 2025
Aeonea logo
Aeonea
Medium
Software Engineer

Find two numbers summing to target

Given an unsorted integer array and a target value, return the indices of two distinct elements whose sum equals the target. Aim for an O(n) time solu...

Coding & Algorithms
1
0
10 people solved
Sep 6, 2025
Aeonea logo
Aeonea
Medium
Software Engineer

Implement a tennis score tracker

Design and implement a tennis game scoring function. Input: a stream of points won by players 'A' or 'B' (e.g., A, B, B, B, B). After each point, outp...

Coding & Algorithms
0
0
7 people solved
Sep 6, 2025
Cisco logo
Cisco
Medium
Software Engineer

Solve max-subarray, min-unique, and grid-jump

1) Given an integer array nums, find a contiguous subarray with the maximum possible sum. Return (maxSum, startIndex, endIndex). If multiple subarrays...

Coding & Algorithms
0
0
11 people solved
Sep 6, 2025
Palo Alto Networks logo
Palo Alto Networks
Medium
Software Engineer

Design an O(1) eviction cache

Implement an in-memory key–value cache with fixed capacity that evicts the least recently used entry when full. Support get(key) -> value or -1 if mis...

Coding & Algorithms
1
0
3 people solved
Sep 6, 2025
Amazon logo
Amazon
Medium
Software Engineer

Find earliest time password becomes irrecoverable

You are given a password string of length n and an attack order array attackOrder[1..n], a permutation of 1..n. At second i (1-indexed), the virus rep...

Coding & Algorithms
1
0
9 people solved
Sep 6, 2025
Datadog logo
Datadog
Medium
Software Engineer

Implement write with internal buffer

Implement a buffered writer over an expensive sink API. You are given a function writeToDevice(byte[] chunk) that may accept at most M bytes per call ...

Coding & Algorithms
0
0
8 people solved
Sep 6, 2025
DoorDash logo
DoorDash
Medium
Software Engineer

Design dasher-to-order assignment algorithm

You are building a real-time 'dasher picker' that assigns delivery drivers (Dashers) to incoming orders. Define objective(s) (e.g., minimize ETA and c...

Coding & Algorithms
1
0
13 people solved
Sep 6, 2025
Amazon logo
Amazon
Medium
Software Engineer

Find returning users from access logs

Given an unordered log of web access events, identify which users are returning (i.e., they have visited on at least two different calendar days). Eac...

Coding & Algorithms
1
0
8 people solved
Sep 6, 2025
Meta logo
Meta
Medium
Software Engineer

Design an in-memory database with TTL and history

Design and implement an in-memory key–field–value store with monotonic timestamps. Keys and fields are strings; values are integers. Provide these API...

Coding & Algorithms
9
0
100 people solved
Sep 6, 2025
Meta logo
Meta
Medium
Software Engineer

Implement power and balance-parentheses algorithms

Design and implement two algorithms: 1) Fast exponentiation: Implement a function pow(x, n) that returns a real number x raised to an integer exponent...

Coding & Algorithms
2
0
31 people solved
Sep 6, 2025
Meta logo
Meta
Medium
Software Engineer

Implement BST vertical traversal and list conversion

Given the root of a binary search tree (BST): 1) Implement vertical order traversal: assign the root column 0, left child column −1, right child colum...

Coding & Algorithms
2
0
46 people solved
Sep 6, 2025
Coinbase logo
Coinbase
Medium
Software Engineer

Implement banking ops: transfer, top-k, cashback, merge

Design and implement an in-memory banking system that supports: ( 1) CreateAccount(id, initialBalance) and Transfer(fromId, toId, amount) with validat...

Coding & Algorithms
15
0
132 people solved
Sep 6, 2025
Moveworks logo
Moveworks
Medium
Software Engineer

Select next Hangman letter

Given the current state of a Hangman game, implement a function that selects the next letter with the highest likelihood of appearing in the secret wo...

Coding & Algorithms
17
0
165 people solved
Sep 6, 2025
Motive logo
Motive
Medium
Software Engineer

Implement Union-Find and track components

Implement a Disjoint Set Union (Union-Find) data structure with union by rank and path compression. Design the API to support union(a, b), connected(a...

Coding & Algorithms
5
0
41 people solved
Sep 6, 2025

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