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Every link, in one place

The shelf below is what to keep bookmarked all year. Underneath it, every reference from every stage is grouped by the topic it belongs to, so you can go straight to the right one without hunting through the roadmap. 108 links in total.

Keep these open all year

Python for EverybodyCourseA complete free course for absolute beginners. The best single starting point for weeks 1 to 12.py4e.com The Python tutorialDocsThe official walkthrough of the language. Terse, and always correct.docs.python.org/3/tutorial/index.html Automate the Boring StuffBookFree online book. Practical projects, very readable.automatetheboringstuff.com VisuAlgoVisualAnimated visualisations of nearly every structure in this roadmap. When something will not click, come here first.visualgo.net/en Big-O cheat sheetVisualOne page listing the speed of every structure and sort. Keep it bookmarked from week 13 onwards.bigocheatsheet.com Khan Academy — AlgorithmsCourseFree and beginner-friendly. The gentlest correct treatment of the core algorithms.khanacademy.org/computing/computer-science/algorithms MIT 6.006 — Introduction to AlgorithmsVideoA full MIT course, free. Harder than Khan Academy. Its dynamic programming lectures are the best available anywhere.ocw.mit.edu/courses/6-006-introduction-to-algorithms-spring-2020 MIT 6.046 — Design and Analysis of AlgorithmsVideoThe advanced follow-up. Only after 6.006.ocw.mit.edu/courses/6-046j-design-and-analysis-of-algorithms-spring-2015 GeeksforGeeks DSA hubDocsEnormous coverage with code for everything. Quality varies; good for a second explanation.geeksforgeeks.org/dsa/dsa-tutorial-learn-data-structures-and-algorithms CP-AlgorithmsDocsRigorous, careful write-ups. Harder going, and the one to trust when other sources disagree.cp-algorithms.com CLRS — Introduction to AlgorithmsBookThe standard academic reference. A paid book, and not a first read — use it to look things up.mitpress.mit.edu/9780262046305/introduction-to-algorithms NeetCode roadmapPracticePractice problems grouped by pattern. The NeetCode 150 maps cleanly onto weeks 15 to 34.neetcode.io/roadmap LeetCodePracticeThe largest problem set. Use NeetCode to decide what to solve here, or you will grind aimlessly.leetcode.com HackerRank — data structuresPracticeAn alternative problem set, with a gentler difficulty curve than LeetCode.hackerrank.com/domains/data-structures roadmap.sh — DSA curriculumDocsThe curriculum this track is structured on.roadmap.sh/datastructures-and-algorithms

Week 0 · Getting your computer ready

What Python actually is

Download PythonDocsThe official installer. On Windows, tick the box that says “Add Python to PATH” — without it, your terminal will not find Python.python.org/downloads

What a code editor is for

Download VS CodeDocsThe editor itself. Free, no account needed.code.visualstudio.com Python extension for VS CodeDocsInstall this after VS Code. It adds Python understanding, running, and debugging.marketplace.visualstudio.com/items VS Code Python setup walkthroughDocsStep by step with screenshots. Go here first if anything above does not work.code.visualstudio.com/docs/python/python-tutorial

Weeks 1–3 · Telling the computer what to do

Variables and types

Python tutorial: an informal introductionDocsThe official first chapter. Covers numbers and strings from zero.docs.python.org/3/tutorial/introduction.html Python for Everybody — Dr ChuckCourseA free full course, genuinely paced for people who have never programmed. The best single starting point if the official docs feel dry.py4e.com

Getting information in and out

Python tutorial: input and outputDocsThe official reference for printing and f-strings.docs.python.org/3/tutorial/inputoutput.html

Operators — doing things to values

Python tutorial: numbers and operatorsDocsOfficial coverage of arithmetic, including integer division and remainder.docs.python.org/3/tutorial/introduction.html

Conditionals — making decisions

Python tutorial: control flowDocsOfficial coverage of if, elif and else, then loops.docs.python.org/3/tutorial/controlflow.html

Loops — repeating work

Python tutorial: for statements and range()DocsOfficial coverage, including the range() function and how its counting works.docs.python.org/3/tutorial/controlflow.html Automate the Boring Stuff, chapters 1–2BookFree online book. Very practical, with lots of small runnable examples.automatetheboringstuff.com

Indentation is not decoration

Python style guide: indentationDocsThe community convention — four spaces per level. Worth skimming once.peps.python.org/pep-0008

Weeks 4–6 · Reusable steps, and Python's built-in containers

Functions

Python tutorial: defining functionsDocsOfficial coverage of def, parameters, defaults and return values.docs.python.org/3/tutorial/controlflow.html Python for Everybody — chapter 4, functionsCourseBeginner-paced video and text on the same material.py4e.com/lessons

Scope — where a name is visible

Python tutorial: scopes and namespacesDocsThe official explanation. Slightly dense — read it after you have written a few functions.docs.python.org/3/tutorial/classes.html

Lists

Python tutorial: data structuresDocsThe single most useful page in the Python docs for this stage. Covers lists first, then dictionaries, tuples and sets.docs.python.org/3/tutorial/datastructures.html

Dictionaries

Python docs: dictionariesDocsThe complete reference for what a dictionary can do.docs.python.org/3/library/stdtypes.html

Tuples and sets

Python docs: set typesDocsWhat sets can do, including union and intersection.docs.python.org/3/library/stdtypes.html

List comprehensions

Python tutorial: list comprehensionsDocsOfficial explanation with several worked examples.docs.python.org/3/tutorial/datastructures.html

Weeks 7–9 · Reading crashes, working with files, and finding bugs

Reading a stack trace

Python tutorial: errors and exceptionsDocsOfficial explanation of what the different errors mean and how to handle them.docs.python.org/3/tutorial/errors.html Python docs: list of built-in exceptionsDocsLook up any error name you do not recognise here.docs.python.org/3/library/exceptions.html

Handling exceptions

Python tutorial: handling exceptionsDocstry, except, else and finally, with examples.docs.python.org/3/tutorial/errors.html

Reading and writing files

Python tutorial: reading and writing filesDocsOfficial coverage, including the with pattern.docs.python.org/3/tutorial/inputoutput.html Python docs: the csv moduleDocsFor anything spreadsheet-shaped. Read the reader and DictReader sections.docs.python.org/3/library/csv.html

Debugging

VS Code: Python debuggingDocsHow to set breakpoints and step through code in the editor you are already using.code.visualstudio.com/docs/python/debugging Python docs: pdb, the built-in debuggerDocsThe terminal-based debugger, for when you are not in an editor. Worth knowing it exists.docs.python.org/3/library/pdb.html

Modules — splitting code across files

Python tutorial: modulesDocsimport, from-import, and how Python finds your files.docs.python.org/3/tutorial/modules.html The Python standard library indexDocsEverything that comes free with Python. Skim the contents page once so you know what is there.docs.python.org/3/library/index.html

Weeks 10–12 · Building your own kinds of thing

Classes and objects

Python tutorial: classesDocsThe official chapter. Sections 9.3 and 9.4 are the ones that matter most right now.docs.python.org/3/tutorial/classes.html Real Python: object-oriented programmingCourseA gentler, example-heavy walkthrough if the official docs move too fast.realpython.com/python3-object-oriented-programming

Making objects printable

Python docs: the data modelDocsThe reference for __str__, __repr__ and the other special methods. Dense — use it as a lookup, not a read-through.docs.python.org/3/reference/datamodel.html

Composition — objects holding other objects

GeeksforGeeks: Python OOP conceptsDocsExtra worked examples of classes holding other objects.geeksforgeeks.org/python/python-oops-concepts

A gentle first look at recursion

Khan Academy: recursionCourseFree, visual, and paced for people meeting the idea for the first time.khanacademy.org/computing/computer-science/algorithms/recursive-algorithms/a/recursion Python docs: the recursion limitDocsWhy deep recursion stops, and the switch that changes the limit. Read it; do not raise it.docs.python.org/3/library/sys.html

Weeks 13–14 · How to say whether code is fast

Big-O notation

Khan Academy: asymptotic notationCourseThe gentlest correct introduction. Start here if the idea is new.khanacademy.org/computing/computer-science/algorithms/asymptotic-notation/a/asymptotic-notation Big-O cheat sheetVisualA one-page table of the cost of every structure and sort in this roadmap. Bookmark it — you will use it all year.bigocheatsheet.com MIT 6.006, lecture 1VideoA full university course, free. Lecture 1 covers this rigorously. Harder going than Khan Academy — come back once the basics land.ocw.mit.edu/courses/6-006-introduction-to-algorithms-spring-2020 GeeksforGeeks: analysis of algorithmsDocsWorked examples of deriving the cost of small pieces of code.geeksforgeeks.org/dsa/analysis-of-algorithms-set-1-asymptotic-analysis

Recursion and the call stack

Khan Academy: recursive algorithmsCourseVisual, beginner-paced treatment with worked examples.khanacademy.org/computing/computer-science/algorithms/recursive-algorithms/a/recursion GeeksforGeeks: introduction to recursionDocsMany small examples, useful for drilling the base-case habit.geeksforgeeks.org/dsa/introduction-to-recursion-data-structure-and-algorithm-tutorials Python docs: the recursion limitDocsWhat the limit is and why it exists.docs.python.org/3/library/sys.html

The small amount of maths you need

Khan Academy: modular arithmeticCourseClock arithmetic explained from scratch, no prerequisites.khanacademy.org/computing/computer-science/cryptography/modarithmetic/a/what-is-modular-arithmetic CP-Algorithms: number theoryDocsRigorous write-ups. Harder than Khan Academy — use as a reference rather than a first read.cp-algorithms.com/algebra/binary-exp.html

Weeks 15–19 · Structures that lay things out in a line

Arrays and dynamic arrays

Python tutorial: data structuresDocsWhat Python lists can do. Your daily reference.docs.python.org/3/tutorial/datastructures.html GeeksforGeeks: array data structure guideDocsBroad coverage with diagrams and practice problems.geeksforgeeks.org/dsa/array-data-structure-guide

Linked lists

GeeksforGeeks: linked listDocsThe most complete free walkthrough, with all the standard operations drawn out.geeksforgeeks.org/dsa/linked-list-data-structure Python docs: collections.dequeDocsPython's built-in doubly linked list. Use this rather than your own, after you have written one once.docs.python.org/3/library/collections.html VisuAlgo: linked list animationVisualWatch the pointers rewire step by step. Far clearer than a static diagram.visualgo.net/en/list

Stacks

Python: using lists as stacksDocsYou do not need a special class in Python — append and pop already give you a stack.docs.python.org/3/tutorial/datastructures.html GeeksforGeeks: stack data structureDocsFull coverage plus the standard problems.geeksforgeeks.org/dsa/stack-data-structure

Queues, deques and priority queues

Python docs: heapqDocsPython's priority queue. The page includes a genuinely good explanation of the theory.docs.python.org/3/library/heapq.html GeeksforGeeks: queue data structureDocsAll the queue variants with diagrams.geeksforgeeks.org/dsa/queue-data-structure

Hash tables

GeeksforGeeks: hashingDocsHash functions, collisions and resizing, with the diagrams you need to build one.geeksforgeeks.org/dsa/hashing-data-structure Python docs: how objects are hashedDocsWhat Python requires of a key, and why lists cannot be keys.docs.python.org/3/reference/datamodel.html VisuAlgo: hash table animationVisualWatch collisions happen and get resolved.visualgo.net/en/hashtable

Strings

Python docs: string methodsDocsThe full list of what strings can do. Read it once; you will keep coming back.docs.python.org/3/library/stdtypes.html

Weeks 20–25 · Trees and graphs

Trees and binary trees

VisuAlgo: binary tree visualiserVisualWatch traversals happen node by node. The single most useful resource for this stage.visualgo.net/en/bst GeeksforGeeks: tree data structureDocsComplete coverage with the terminology laid out clearly.geeksforgeeks.org/dsa/tree-data-structure

Binary search trees

VisuAlgo: BST visualiserVisualInsert sorted values and watch it collapse into a chain. Worth doing deliberately.visualgo.net/en/bst GeeksforGeeks: binary search treeDocsAll operations including the fiddly delete case.geeksforgeeks.org/dsa/binary-search-tree-data-structure

Self-balancing trees, and why databases care

GeeksforGeeks: AVL treesDocsThe clearest introduction to rotations. Start here.geeksforgeeks.org/dsa/introduction-to-avl-tree GeeksforGeeks: B-treesDocsWhy wide and shallow beats narrow and deep when disks are involved.geeksforgeeks.org/dsa/introduction-of-b-tree-2 PostgreSQL: B-tree indexesDocsA real production database explaining its own index structure. Read this to see the theory used in earnest.postgresql.org/docs/current/btree.html

Heaps

Python docs: heapqDocsPython's implementation, with an unusually good theory section at the bottom of the page.docs.python.org/3/library/heapq.html VisuAlgo: heap animationVisualWatch items bubble up and sink down. Makes the algorithm obvious.visualgo.net/en/heap

Tries

GeeksforGeeks: trie insert and searchDocsThe clearest walkthrough of building one.geeksforgeeks.org/dsa/trie-insert-and-search

Graphs

VisuAlgo: graph structuresVisualBuild a graph and see both storage forms side by side.visualgo.net/en/graphds GeeksforGeeks: graph data structure and algorithmsDocsThe hub page. Everything about graphs links from here.geeksforgeeks.org/dsa/graph-data-structure-and-algorithms

Union-find

GeeksforGeeks: disjoint set and union-findDocsStep by step, including both optimisations.geeksforgeeks.org/dsa/introduction-to-disjoint-set-data-structure-or-union-find-algorithm CP-Algorithms: disjoint set unionDocsA more rigorous treatment with proofs, once the basic version makes sense.cp-algorithms.com/data_structures/disjoint_set_union.html

Weeks 26–30 · The classic algorithms

Binary search

Khan Academy: binary searchCourseThe clearest beginner explanation, with the boundary pitfalls called out.khanacademy.org/computing/computer-science/algorithms/binary-search/a/binary-search Python docs: the bisect moduleDocsPython's built-in correct implementation. Use it in real code once you have written your own.docs.python.org/3/library/bisect.html

Sorting

VisuAlgo: sorting animationsVisualWatch every sort run side by side on the same data. The fastest way to understand the differences.visualgo.net/en/sorting Khan Academy: merge sortCourseCareful beginner walkthrough of the divide-and-combine idea.khanacademy.org/computing/computer-science/algorithms/merge-sort/a/overview-of-merge-sort Python: sorting HOWTODocsHow to sort by custom keys in real code. Immediately practical.docs.python.org/3/howto/sorting.html The Timsort design notesDocsThe actual engineering notes for Python's sort. Dense, and a genuinely interesting read once sorting makes sense.github.com/python/cpython/blob/main/Objects/listsort.txt

Breadth-first and depth-first search

Khan Academy: breadth-first searchCourseBeginner-paced, with the shortest-path property explained properly.khanacademy.org/computing/computer-science/algorithms/breadth-first-search/a/breadth-first-search-and-its-uses GeeksforGeeks: BFSDocsCode and worked examples.geeksforgeeks.org/dsa/breadth-first-search-or-bfs-for-a-graph GeeksforGeeks: DFSDocsThe same for depth-first, including recursive and iterative versions.geeksforgeeks.org/dsa/depth-first-search-or-dfs-for-a-graph

Shortest paths

GeeksforGeeks: Dijkstra explainedDocsA gentle walkthrough with diagrams. Read this first.geeksforgeeks.org/dsa/dijkstras-shortest-path-algorithm-greedy-algo-7 CP-Algorithms: DijkstraDocsCareful and correct. The reference to work from when you implement it.cp-algorithms.com/graph/dijkstra.html CP-Algorithms: Bellman-FordDocsNegative weights and negative-cycle detection.cp-algorithms.com/graph/bellman_ford.html

Minimum spanning trees

CP-Algorithms: KruskalDocsThe algorithm and its union-find pairing.cp-algorithms.com/graph/mst_kruskal.html CP-Algorithms: PrimDocsThe alternative approach, with the heap-based version.cp-algorithms.com/graph/mst_prim.html

Topological sort

GeeksforGeeks: topological sortingDocsBoth methods with worked examples.geeksforgeeks.org/dsa/topological-sorting CP-Algorithms: topological sortDocsA tighter treatment of the depth-first version.cp-algorithms.com/graph/topological-sort.html

Weeks 31–34 · Choosing the right approach

Brute force

GeeksforGeeks: brute force approachDocsWhen it is acceptable and when it is not.geeksforgeeks.org/dsa/brute-force-approach-and-its-pros-and-cons

Divide and conquer

GeeksforGeeks: the Master TheoremDocsHow to get the cost of a divide-and-conquer algorithm without guessing.geeksforgeeks.org/dsa/advanced-master-theorem-for-divide-and-conquer-recurrences MIT 6.046: divide and conquerVideoThe advanced MIT course. Rigorous; use it once the basics are comfortable.ocw.mit.edu/courses/6-046j-design-and-analysis-of-algorithms-spring-2015

Greedy algorithms

GeeksforGeeks: greedy algorithmsDocsThe hub page, with the standard problems.geeksforgeeks.org/dsa/greedy-algorithms GeeksforGeeks: Huffman codingDocsA greedy algorithm you use every day without knowing it.geeksforgeeks.org/dsa/huffman-coding-greedy-algo-3

Backtracking

GeeksforGeeks: backtrackingDocsThe pattern and the classic problems.geeksforgeeks.org/dsa/backtracking-algorithms Python docs: itertoolsDocsBuilt-in tools for permutations and combinations, so you do not hand-roll them.docs.python.org/3/library/itertools.html

Dynamic programming

MIT 6.006: the dynamic programming lecturesVideoThere are four of them and they are the best free explanation available. Watch all four.ocw.mit.edu/courses/6-006-introduction-to-algorithms-spring-2020 GeeksforGeeks: dynamic programmingDocsThe hub, with every canonical problem worked through.geeksforgeeks.org/dsa/dynamic-programming Python docs: functools.cacheDocsOne decorator that turns a slow recursion into a fast one. Try it on your Fibonacci immediately.docs.python.org/3/library/functools.html

Two pointers, sliding windows and prefix sums

GeeksforGeeks: two pointersDocsThe technique with worked examples.geeksforgeeks.org/dsa/two-pointers-technique GeeksforGeeks: sliding windowDocsFixed and variable window sizes.geeksforgeeks.org/dsa/window-sliding-technique NeetCode roadmapPracticeProblems grouped by pattern rather than by topic, which is exactly what this stage is training.neetcode.io/roadmap

Bit manipulation

GeeksforGeeks: bit manipulation tacticsDocsThe standard tricks in one place.geeksforgeeks.org/dsa/bits-manipulation-important-tactics Python docs: int.bit_countDocsThe built-in version of the counting trick.docs.python.org/3/library/stdtypes.html

Weeks 35–36 and beyond · Optional depth

Segment trees and Fenwick trees

CP-Algorithms: segment treeDocsThe thorough treatment. Long, and correct.cp-algorithms.com/data_structures/segment_tree.html CP-Algorithms: Fenwick treeDocsThe compact alternative.cp-algorithms.com/data_structures/fenwick.html

String search algorithms

CP-Algorithms: prefix function and KMPDocsThe clearest correct explanation of the failure table.cp-algorithms.com/string/prefix-function.html GeeksforGeeks: KMPDocsA gentler walkthrough with diagrams.geeksforgeeks.org/dsa/kmp-algorithm-for-pattern-searching

Network flow

CP-Algorithms: Edmonds-KarpDocsThe standard approachable implementation.cp-algorithms.com/graph/edmonds_karp.html

Randomised and approximate algorithms

GeeksforGeeks: randomized algorithmsDocsOverview with the main techniques.geeksforgeeks.org/dsa/randomized-algorithms

P, NP and what cannot be done quickly

GeeksforGeeks: NP-completenessDocsA readable introduction that does not assume a maths degree.geeksforgeeks.org/dsa/introduction-to-np-completeness