Sofi Software Engineer Interview Questions

Sofi Tech Phone Screen: Anagram Replacement Coding Challenge

This post was last edited by juliaxx on 2025-09-25 12:10. Given a list of string wordset containing anagrams, and a list of strings containing sentences. You can replace words in sentences with anagra

Sofi Onsite 4-Round Fulltime SDE Interview Experience

The following content requires a score higher than 220. You can already view it. The first round only allowed Java; no other languages were permitted. The interviewer added other languages, which migh

#347 Top K Frequent Elements

LeetCode #347: Top K Frequent Elements. Difficulty: Medium. Topics: Array, Hash Table, Divide and Conquer, Sorting, Heap (Priority Queue), Bucket Sort, Counting, Quickselect. Asked at SoFi in the last 6 months.

#380 Insert Delete GetRandom O(1)

LeetCode #380: Insert Delete GetRandom O(1). Difficulty: Medium. Topics: Array, Hash Table, Math, Design, Randomized. Asked at SoFi in the last 6 months.

Count completed trips from vehicle event logs (entry -> road -> exit)

## Problem You are given text logs for multiple vehicles (each record includes a license plate and an event type). Event types are: `entry`, `road`, `exit`. A **trip** is counted when the **same plat

LeetCode 1198 — Find Smallest Common Element in All Rows

Given an `m x n` integer matrix `mat` where each row is sorted in **non-decreasing** order, find the smallest integer that appears in **every row**. - Return the smallest such integer if it exists. -

Implement Button-Triggered Fetch with Lazy Loading in Vanilla JavaScript

## Task: Implement Button-Triggered Fetch + Lazy Loading in Vanilla JavaScript (No Frameworks) On a simple web page (you may build on the previous HTML structure), implement **vanilla JavaScript** lo

Build a Search Bar with HTML/CSS (No Framework)

## Task: Build a Search Bar UI Using Only HTML + CSS (No Frameworks) Implement a search bar UI using **only HTML and CSS** (no frameworks or component libraries). ### Functional & structural require

K-th Unique Maximum from Two Sorted Arrays

## Problem: K-th Unique Maximum from Two Sorted Arrays Given two **ascending sorted** integer arrays `A` and `B` (each may contain duplicates) and an integer `K`, return the `K`-th element in the seq

RunCollection: Simulate chance of matching or beating personal best

### Coding: Monte Carlo probability that an in-progress run matches or beats the personal best You are implementing a statistics system for obstacle-course racing. - A `Course` has `obstacle_count`

Second Most Frequent Tag from Flattened Triples

## Problem: Find the Second Most Frequent Tag from a Flattened String List You are given a string list `arr` whose elements repeat in the following fixed order: ``` [id1, name1, tag1, id2, name2, ta

Design a Multi-threaded Task Executor with Extensible Task Types (Semaphore-based)

## Problem: Design and Implement an Extensible Multi-threaded Task Executor (Semaphore-based) You are given a Java `TaskExecutor` skeleton and must implement a **multi-threaded task executor** using

Count Complete Highway Journeys from Sensor Logs

A highway has multiple sensor locations: **entry**, **exit**, and intermediate **checkpoints**. Each sensor logs when a car passes. You are given time-ordered logs `logs`. Each log entry indicates th

Debug a Journey Counting Implementation

You are given an existing JavaScript implementation and its unit tests. At least one test is failing. Tasks: - Read the code and tests - Identify why the test fails - Fix the code so that all tests p

Graph Variant: Endings Reachable Only If Both Options Are Explored (Follow-up)

Follow-up to the previous problem: model everything as a directed graph (nodes are story segments; edges are option transitions). Add a constraint: For a node with `choice = [start, op1, op2]`, an en