Encode and Decode TinyURL
A medium-tier problem at 86% community acceptance, tagged with Hash Table, String, Design. Reported in interviews at Shopify and 1 others.
Encode and Decode TinyURL lands on your assessment more often than you'd think, especially at Shopify and Salesforce. You need to design a system that converts long URLs into short codes and back again. The trap is overthinking it. Most candidates either bloat the hash function or miss that you're building a stateful service that needs to map codes to URLs consistently. If you freeze during the live OA, StealthCoder surfaces a working bidirectional mapping in seconds, invisible to the proctor.
Companies that ask "Encode and Decode TinyURL"
Encode and Decode TinyURL is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Made for the engineer who has done the work but might still blank with a webcam pointed at him.
Get StealthCoderThe real trick here is recognizing this isn't a cryptography problem. You're designing a simple key-value store where the key is a short string and the value is the original URL. The encode function generates a unique code (usually base62 or base64 encoding of an incrementing counter, or a random string with collision handling). Decode just looks it up. Most candidates fail because they try to make the hash reversible or worry about real-world collision rates. The actual gotcha is statefulness: your encoded URL must always decode to the same original. If you hit this live and blank on the mapping strategy, StealthCoder hands you a working solution that handles both directions and collision avoidance.
Pattern tags
You know the problem.
Make sure you actually pass it.
Encode and Decode TinyURL recycles across companies for a reason. It's medium-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Made for the engineer who has done the work but might still blank with a webcam pointed at him. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Encode and Decode TinyURL interview FAQ
Is this really asked at FAANG-adjacent companies like Shopify?+
Yes. Shopify and Salesforce both report asking this. It's a design question that filters for systems thinking, not just algorithm skill. The acceptance rate is high (86%), so preparation pays off hard.
What's the trick most people miss?+
Thinking the encoding has to be cryptographically secure or mathematically reversible. You're just mapping. Build a bidirectional hash table. Encode generates or retrieves a short code tied to a counter or random string. Decode looks it up. Done.
Do I need to handle collisions?+
Depends on your strategy. If you use a counter, no collisions. If you use randomization, yes, and you check if the code exists before returning it. Most interviewers accept the simple counter approach. Don't overcomplicate.
How does this relate to Hash Table design?+
It's the canonical example. You're implementing a hash map at the problem level, not using a library one. Understanding hash collisions, load factors, and key uniqueness directly applies here. It tests whether you can reason about data structure trade-offs.
What language should I code this in?+
Pick one you're fast in. The logic is identical across Python, Java, Go, or JS. You'll spend more time on clarity than syntax. Focus on the bidirectional mapping and how you generate or manage short codes.
Want the actual problem statement? View "Encode and Decode TinyURL" on LeetCode →