11 — itertools & functools

How two small standard-library modules replace hand-rolled nested loops and memoization boilerplate with composable, lazy building blocks — and where reaching for the library instead of writing the loop yourself stops being free.

4 — Bitmasking

Representing a subset as bits in a single integer — the trick that turns small-universe subset enumeration and subset-indexed DP into plain integer arithmetic, and stops working the moment the universe passes about 25 elements.

Data Structures & Algorithms

A book-shaped table of contents for MAANG-interview DSA prep: Python language foundations, mathematical and algorithmic foundations, arrays/strings, linked structures, stacks/queues, trees, graphs, sorting/searching, dynamic programming, greedy algorithms, backtracking, bit manipulation, advanced data structures, advanced algorithms, interview problem patterns, and MAANG interview mastery — a book-length progression from fundamentals to Google/Meta/Amazon/Apple/Netflix/Microsoft (L4–L6) interview readiness.

1 — Backtracking

The choose-explore-unchoose template and pruning strategies that make exhaustive search tractable.

2 — N Queens

Placing N non-attacking queens via backtracking with row/column/diagonal constraint tracking.

3 — Sudoku Solver

Constraint-propagation backtracking over a 9×9 grid with row/column/box validity checks.

4 — Permutations

Generating all orderings of a set via backtracking, including the handling of duplicate elements.