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Sung M. Kim
Sung M. Kim

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Space-time tradeoff Emoji Note

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

β°πŸ”½πŸ’½πŸ”Ό (faster + more space) vs β°πŸ”ΌπŸ’½πŸ”½ (slower + less space)
πŸ™„πŸ“‘ (Lookup table) πŸ”ƒπŸ’» (Recalculation)
πŸ’Ύ x 1 (Uncompressed Data) πŸ’Ύ x 0.5 (Compressed Data)
πŸͺπŸ–Ό (Stored Image) πŸ”ƒπŸ“œ (Re-render)
➿➑➰ (Loop Unrolling) πŸ‘¨β€πŸ’» x 0.5 (Smaller code)

Gist of each tradeoff

  1. πŸ™„πŸ“‘(Lookup table) vs. πŸ”ƒπŸ’» (Recalculation)
    Saving computed data in memory saves time but increases the space usage.

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

  3. πŸͺπŸ–Ό (Stored Image) vs. πŸ”ƒπŸ“œ (Re-render)
    Storing image in cache is faster than re-rendering but requires more space (in disk/memory).

  4. ➿➑➰ (Loop Unrolling) vs. πŸ‘¨β€πŸ’» 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 πŸ™‚

Top comments (4)

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

Thanks @jeikabu .
You are getting somewhere with that coffee table book idea πŸ™‚

thejoezack profile image
Joe Zack

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

dance2die profile image
Sung M. Kim

Just {...πŸ’–} of Emojis πŸ˜‰