Instacart Coding Interview Questions
28 Instacart coding interview problems with full optimal solutions — 16 easy, 10 medium, 2 hard. Every problem ships with multiple approaches (brute-force first, then the optimal), complexity tables for each, company-specific tips on what an Instacart interviewer values, and a FAQ section.
Showing 10 problems of 28
- #17mediumfoundational
17. Number of Islands
Count connected land regions in a 2D grid — Instacart interviewers use this to test whether you can model a store's floor-map zones and traverse them efficiently for pick-path planning.
- #18mediumfoundational
18. Meeting Rooms II
Find the minimum number of rooms required to schedule overlapping meetings — Instacart mirrors this directly onto delivery-window scheduling where overlapping shopper slots compete for the same fulfillment capacity.
- #19mediumfoundational
19. Top K Frequent Elements
Return the k most frequently occurring integers — Instacart uses frequency ranking everywhere from surfacing top-ordered items to ranking stores by pickup volume in real-time catalog queries.
- #20mediumfoundational
20. Word Break
Determine if a string can be segmented using a dictionary — Instacart applies this DP pattern when parsing user-typed grocery queries that contain concatenated product tokens against the catalog word list.
- #21mediumfoundational
21. Network Delay Time
Find the time for a signal to reach all nodes in a weighted graph — Instacart uses this exact shortest-path pattern to estimate worst-case delivery propagation across its fulfillment network.
- #22mediumfoundational
22. Insert Interval
Insert a new interval into a sorted, non-overlapping list and merge as needed — Instacart uses this when a new delivery window is injected into an existing shopper schedule without disturbing confirmed slots.
- #23mediumfoundational
23. Coin Change
Find the minimum number of coins that sum to an amount — Instacart draws on this classic DP pattern when computing the fewest batch trips a shopper should make to cover a list of item weights optimally.
- #25mediumfoundational
25. LRU Cache
Design a cache that evicts the least recently used item when full — Instacart caches store inventory snapshots in memory for sub-millisecond catalog reads; LRU eviction keeps the hottest stores resident.
- #26mediumfoundational
26. Course Schedule
Detect whether a set of prerequisite dependencies contains a cycle — Instacart uses topological-sort cycle detection when validating that recipe ingredient substitution chains don't loop back on themselves.
- #27mediumfoundational
27. K Closest Points to Origin
Find the k nearest pickup points to a warehouse — Instacart's last-mile team uses this to assign the closest available shoppers to a new order when multiple drivers are in range.