Gotchas

Gotcha	Python	Java	JavaScript
Integer Division	(low + high) // 2	(low + high) / 2 ⚠️ Overflow risk! Better: low + (high - low) / 2	Math.floor((low + high) / 2)
Array Length	len(arr)	arr.length	arr.length
Function Definition	def binary_search():	public static Integer binarySearch()	function binarySearch()
Variable Declaration	low = 0	int low = 0;	let low = 0;
Equality Check	==	== (primitives) equals() (objects)	=== (strict) == (loose, avoid!)
Null/None Value	None	null	null
Return Type	Dynamic	Must declare Integer (not int) to return null	Dynamic
Naming Convention	snake_case	camelCase	camelCase
Division Behavior	/ returns float // returns int	/ returns int for integers float for mixed types	/ always returns float
Semicolons	Optional (not used)	Required ;	Optional but recommended ;

Syntax

• In Python, arrays are called lists.
• range(start, stop[, step])

Theory

• Algorithm times are measured in terms of growth of an algorithm.
• Algorithm times are written in big O notation.
• Common big O run times, sorted from fastest to slowest:
  • O(log n), also known as logarithmic time (binary search).
  • O(n), also known as linear time (simple search).
  • O(n * log n), a fast sorting algorithm (quicksort).
  • O(n*n), a slow sorting algorithm (selection sort).
  • O(n!), a really slow algorithm (traveling salesperson).
• Lists are better if you want to insert elements into the middle.
• Linked lists allow fast inserts an deletes.
• Random access (offered by arrays), means you can jump directly to a specific element.
• Arrays are faster because they can use caching.
• Insertions and deletions are O(1), or constant time, only if you can instantly access the element to be deleted.

Tooling

• https://code.visualstudio.com/docs/python/jupyter-support-py#_jupyter-code-cells
• https://code.visualstudio.com/docs/languages/java#_install-a-java-development-kit-jdk
• Execute a Typescript file from CLI: node --experimental-transform-types 01_binarySearch.ts