README.md

practice-problems

Handwritten coding problems I worked through while studying Structure and Interpretation of Computer Programs (SICP), Section 1, alongside courses on boot.dev and general recursion and functional programming practice.

The SICP stuff got me thinking in terms of closures, recursion, higher-order functions, and building up from primitives. These problems are the result of that mindset applied to Python and a bit of Scheme.

Problems

File	What it does
currying.py	Generic curry function that works with any arity, supports partial application in any grouping
memoized_factorial_closure.py	Factorial using a closure-based cache, plus a version with @lru_cache for comparison
depth_weighted_sum.py	Recursively sum integers in arbitrarily nested lists, weighted by their depth
generate_parentheses.py	Generate all valid combinations of n pairs of parentheses using backtracking
recursive_join.py	String join implemented recursively, no built-in join
sum_types.py	Pattern matching on sum types (enums) to build a CSV export state machine
dir_reduc.py	Reduce a list of directions by cancelling opposites
dir_reduc_non_retarded.py	Same problem, cleaner solution
filter_list.py	Filter a mixed list to only integers
palindrome.py	Palindrome checker
phone_number.py	Format digits into a phone number string
recr_sum_postive_numbers.py	Recursive sum of positive numbers
words.py	Word manipulation
scheme/test.scm	First steps in Scheme (SICP Chapter 1)

Running

python <filename>.py

Each file is self-contained with inline test cases.