Shopify 2026 Pair Prgramming In - Shopify

Summary

I had a pair programming interview at Shopify where I was asked to implement a number guessing game.

Full Experience

I had a pair programming interview at Shopify where I was asked to implement the following:

Question:

Implement a NUMBER guessing game. The user must guess a 4-digit number (without repeats). The user has 7 attempts. Every attempted guess must be a 4-digit number.

They either:

wins (guessed the number correctly)
loses (7th attempt is wrong)
or get "tip": X bulls, Y cows, where: X is the number of correct digits in correct positions Y is the number of correct digits, but wrongly positioned.

For example, the number is "1234".

Attempt 1290 will result in a tip: 2 bulls, 0 cows.
Attempt 1234 will be WIN.
Attempt 1562 will result in a tip: 1 bull, 1 cow.

Comments It should be a CLI program.

0123 - an invalid number (can't start with 0)
1023 - is valid
1123 - is invalid (digits repeat). Every time a user starts a game, they should get a random number to guess.

Bonus:

Print "Gutter ball!!!" if the user hits 0 bulls and 0 cows.
Every time the user starts a game, they should get a DIFFERENT number to guess (never repeat the same number)!

Tip:

More than implementation focus on setting up test cases first and be ready to write unit test cases class and test it.

Interview Questions (1)

Number Guessing Game (Bulls and Cows variant)

Data Structures & Algorithms