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Web Collision Detection Optimization
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Web Collision Detection Optimization

HardPython

Problem

How would you optimize a collision detection system for hundreds of architectural objects in a web browser?

Implement the collision query for axis-aligned rectangular objects using a uniform spatial hash. Return every pair whose interiors overlap, excluding objects that only touch at an edge or corner.

Input and Output

detect_collisions(objects, cell_size) receives a list of dictionaries with integer id, x, y, width, and height fields. Return sorted [id1, id2] pairs, with each pair ordered by ID.

Constraints

  • 1 <= len(objects) <= 5000
  • 1 <= cell_size <= 10^6
  • Each object has a unique integer id
  • 0 <= width and height are positive integers
  • -10^9 <= x, y <= 10^9
  • Object rectangles are axis-aligned
  • Return every overlapping pair exactly once

Function Signature

def detect_collisions(objects, cell_size):
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