PHASE 03

#๏ธโƒฃ Hash Maps & Sets

Hashing is the single most useful interview tool. Learn how hash maps work, when to use a set, and the counting and grouping patterns behind dozens of classic questions.

โฑ๏ธ ~2 hours of lessons ๐Ÿ“š 3 lessons โœ๏ธ 8 exercises Easy
โ–ถ Start this phase

๐ŸŽฏ In this phase you willโ€ฆ

  • Explain how a hash table finds things fast
  • Use sets for seen-before checks
  • Use maps for counting, grouping and complements

๐Ÿ“บ Lessons in this playlist

๐Ÿ“ Phase test

Concept questions, pseudocode writing, tracing and debugging โ€” check youโ€™re ready for the next phase.

๐Ÿ’ก Concept check
Which problem is a hash map the natural fit for?