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Counting-Geometry Ladder

Who This Is For

Use this ladder when you trust your geometry primitives but want to learn how to collapse geometric structure into counting structure.

Warm-Up

  • normalize slopes or directions
  • count complementary direction classes

Core

  • sort-or-hash normalized geometry features
  • avoid floating-point comparisons

Example Notes

Exit Criteria

You are ready to move on when you can:

  • define a canonical direction or slope key
  • choose sorting or hashing intentionally
  • explain why the brute-force tuple count collapses after normalization
  • avoid floating-point equality in exact-input problems

External Practice