Skip to content

Tracks

AI-assisted engineering Working with AI Agents System design Core systems Data and AI systems Coding Coding problems Code review On-call SQL

Practice

Paths Concept guides

FreeAd-supported

The plan adds AI feedback and removes ads.

Concept guides/Arrays and strings/Arrays & in-place tricks

CodingArrays and strings

Arrays & in-place tricks

Easy3 min read

Questions it teaches

Three-way partition by pivotEasy15 min Stock spreadEasy10 min Stock replenishmentEasy10 min Apply a flash sale price cap to a cartEasy10 min Zero the stock counts of recalled pallet slotsEasy10 min Show the best price still to comeEasy10 min Carousel rotationEasy12 min Find the first day a shop balance goes negativeEasy10 min

Related

Arrays and strings Searching and sorting Designing data structures Backtracking and games Dynamic programming Data and ML code Front-end code

Leads to: Searching and sorting

Sorting algorithms3 min Two pointers3 min

Leads to: Designing data structures

Queues, deques & ring buffers3 min Database deduplication3 min

Leads to: Backtracking and games

Recursion & backtracking3 min Game theory & Grundy3 min

Leads to: Dynamic programming

Dynamic programming: 2D & strings3 min Dynamic programming: 1D3 min

© 2026 Prep Room·From California·AI can make mistakes.

About Legal Contact Cookies Your privacy choices

Home Review Tracks Paths