Instacart Senior (L6) Software Engineer Interview Experience — Grocery Pricing Coding, Inventory System Design, and a 20-Minute Behavioral

Two coding rounds, one system design round, and one behavioral round.

Coding question 1

Given input strings in the format SKUid|SKUNAME|QUANTITY|Price, output the total quantity and the total price in dollars. The price in the input is in cents. Watch out for bad input.

Besides the input above, there is also a discount input, in the formats SKUid|axf|20 and SKUid|bxf|5|2. The first format is a 20% discount, the second is buy five get two free. Each SKU may have multiple promotions; pick the promotion option that leaves the lowest price.

APPle|aisle|false: the SKU id, the aisle number, and whether it is frozen. Sort the output by aisle, and put the frozen products at the end.

Coding question 2

T1, T1 = T2, T2 = 5: output the result for T1.

Next part: the expression may have + or -.

Third part: there may be a cycle.

Behavioral questions

Project, mentoring, trade-offs, disagreement, etc.

System design

Inventory management service.

Concurrency, hot SKUs, reservations, overselling, partial fulfillment, etc.

I feel like I failed on the behavioral. It was a 45-minute interview and they only asked questions for 20 minutes. Maybe they just weren't that interested in my project.