Space-time tradeoff Emoji Note

dance2die profile image Sung M. Kim ・2 min read

Anthony has shared wonderful tips on interviewing at Google.

Within the fourth tip, Brainstorm solutions and their time/space complexity, Anthony stressed on "space-time tradeoff principle", which I was vaguely familiar with.

While attempting to understand it, I drew a sketchnote.


As it's not sharable, I came up with emoji version.

Space-time Tradeoff Table

⏰🔽💽🔼 (faster + more space) vs ⏰🔼💽🔽 (slower + less space)
🙄📑 (Lookup table) 🔃💻 (Recalculation)
💾 x 1 (Uncompressed Data) 💾 x 0.5 (Compressed Data)
🏪🖼 (Stored Image) 🔃📜 (Re-render)
➿➡➰ (Loop Unrolling) 👨‍💻 x 0.5 (Smaller code)

Gist of each tradeoff

  1. 🙄📑(Lookup table) vs. 🔃💻 (Recalculation)
    Saving computed data in memory saves time but increases the space usage.

  2. 💾 x 1 (Uncompressed Data) vs. 💾 x 0.5 (Compressed Data)
    Faster to access uncompressed data as no decompression step is needed but requires more space.

  3. 🏪🖼 (Stored Image) vs. 🔃📜 (Re-render)
    Storing image in cache is faster than re-rendering but requires more space (in disk/memory).

  4. ➿➡➰ (Loop Unrolling) vs. 👨‍💻 x 0.5 (Smaller code)
    Loop unrolling can optimize execution speed at the cost of increased binary size.

It might be a bit too much of emojis but helped me to understand a bit better what tradeoffs are available.

Feel free to share your version of table or sketchnote 🙂


Editor guide
jeikabu profile image

This is great. Makes me want an entire CS textbook in emoji. Would make a great coffee table book.

dance2die profile image
Sung M. Kim Author

Thanks @jeikabu .
You are getting somewhere with that coffee table book idea 🙂

thejoezack profile image
Joe Zack

You are truly the emoji master! ?love those sketch notes too)

dance2die profile image
Sung M. Kim Author

Just {...💖} of Emojis 😉