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Data Structures and Algorithms in Dart

Q: Which Dart classes match which data structures?

List is a dynamic array and your stack; Map and Set are hash tables, insertion-ordered by default; dart:collection adds Queue (a ListQueue, a ring buffer, unless you choose DoubleLinkedQueue), LinkedList for entries that extend LinkedListEntry, and SplayTreeMap and SplayTreeSet, self-adjusting ordered trees. For a heap, the Dart team's package:collection provides PriorityQueue. Tries and graphs you write yourself.

Q: Does Dart have a priority queue?

Not in the core SDK. dart:collection stops at queues, linked lists and splay trees, and PriorityQueue lives in package:collection, a package the Dart team maintains but you add yourself. That makes a heap a fair thing for a Dart interview to ask you to write, and step two is where you write one.

Dart's core libraries go further than most, with a Queue, a LinkedList and splay trees in dart:collection, but the core SDK has no heap or priority queue. This path has you build every structure in Dart, where sound null safety makes each missing link a Node? you must check, then sort, recurse and search graphs with them, and finish on graded interview problems. Free, in your browser, with a certificate on most courses.

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377 lessons284 challenges702 quiz questions

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DSA in Dart, step by step

38 courses377 lessons284 challenges702 quiz questions

Each step is a set of existing Coddy courses, and every Start button opens them in Dart. The three courses not taught in Dart yet are listed after the steps.

1
Step 1
Data Structures Series, part one
Start this stepStartStack, queue, binary tree, hash table and linked list, each built from scratch in Dart and then used to solve problems. After it, you know what List, Queue and Map do for you, and why a Map literal remembers the order you inserted its keys.Start
5 courses, in order
66 lessons56 challenges4 projects
2
Step 2
Data Structures Series, part two
Start this stepStartDoubly linked list, heaps and priority queues, tries, graphs and the self-balancing AVL tree. After it, DoubleLinkedQueue is a structure you have written, the heap the core SDK lacks is one you can write, and SplayTreeMap is an ordered tree you understand: self-adjusting where yours is height-balanced.Start
5 courses, in order
72 lessons62 challenges3 projects
3
Step 3
Sorting algorithms
Start this stepStartBubble, selection, insertion, merge, quick, heap, counting and radix sort, written in Dart and watched in the visualizer. List.sort takes a comparator such as (a, b) => a.compareTo(b); after this step you can write the algorithm behind that call.Start
8 courses, in order
74 lessons38 challenges319 questions7 projects
4
Step 4
Recursive thinkingDedicated page
Start this stepStartRecursion challenges in Dart, where null safety makes the base case explicit: a function over a Node? has to deal with null before it can recurse, and type promotion lets it use the node freely after that check. A runaway recursion ends in a StackOverflowError. Dynamic programming and bit manipulation are listed after the steps, since they are taught in Python and C++.Start Dedicated page15 lessons15 challenges
5
Step 5
Graph algorithms
Start this stepStartBreadth-first and depth-first search, Dijkstra, Bellman-Ford, topological sort, Kruskal and Prim in Dart, on the graph you built in step two. The core SDK has no priority queue, so the heap from step two is the one Dijkstra needs.Start
7 courses, in order
63 lessons28 challenges383 questions7 projects
6
Step 6
Interview practice
Start this stepStartTen interview challenge packs and two coding-problem banks in Dart, graded by test cases: unfamiliar problems, solved without a tutorial, with null safety checking every link you follow.Start
12 courses, in order
87 lessons85 challenges

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Why learn DSA in Dart on Coddy

Null safety, where it matters most. A linked list or a tree is references that may be missing, and Dart's sound null safety makes each one a Node? you have to check before you follow it. The null-pointer crash other languages find at runtime, Dart's compiler reports while you are still writing the structure.
Interview prep for Flutter developers. Dart is the language you think in for Flutter, and mobile interviews at many companies include an algorithm round. Flutter's widget tree is a tree too, so the traversals you learn here have the shape of the framework you use every day.
Nearly the whole path in Dart. Every data structure, sort, graph algorithm, recursion challenge and interview pack is taught in Dart. Three are taught elsewhere and listed after the steps with a link to each: dynamic programming and the Python interview series in Python, and bit manipulation in C++. Bit manipulation is an easy read from Dart, which has C++'s &, |, ^, ~, << and >>.
Graded like an interview. Every lesson ends in a Dart challenge checked by test cases, and when one fails, Bugsy reads your code and nudges you toward the fix without handing over the answer. A free certificate on most courses, each verifiable at its own URL.

Frequently asked questions about DSA in Dart

Is Dart good for data structures and algorithms?

Yes. It is typed and class-based, close to Java or C# in shape, so a Node<T> class with a nullable next is exactly what it looks like, and dart:collection covers more than most standard libraries. Two things are worth knowing: the core SDK has no priority queue, and a Map or Set literal is a LinkedHashMap or LinkedHashSet, which remembers insertion order: handy for output, but not the same promise as a sorted map.

Which Dart classes match which data structures?

List is a dynamic array and your stack; Map and Set are hash tables, insertion-ordered by default; dart:collection adds Queue (a ListQueue, a ring buffer, unless you choose DoubleLinkedQueue), LinkedList for entries that extend LinkedListEntry, and SplayTreeMap and SplayTreeSet, self-adjusting ordered trees. For a heap, the Dart team's package:collection provides PriorityQueue. Tries and graphs you write yourself.

Does Dart have a priority queue?

Not in the core SDK. dart:collection stops at queues, linked lists and splay trees, and PriorityQueue lives in package:collection, a package the Dart team maintains but you add yourself. That makes a heap a fair thing for a Dart interview to ask you to write, and step two is where you write one.

What is a splay tree, and when should I use `SplayTreeMap`?

A splay tree is a self-adjusting binary search tree: every access moves the node it touched to the root, so recently used keys are quick to reach again, and operations cost O(log n) amortized, not guaranteed on every single call. Use SplayTreeMap when you need keys in sorted order, the smallest or largest key, or the nearest key on either side of a value, through firstKeyAfter and lastKeyBefore. The AVL tree you build in step two takes the other approach, rebalancing on every change to keep its height strictly bounded.

Which courses on this path are not taught in Dart?

Three: dynamic programming and the Python interview series, taught in Python, and bit manipulation, taught in C++. They are listed after the steps, each with a link that opens it in its own language. A memo in Dart is a List or a Map, and toRadixString(2) prints an int in binary, the quickest way to check what a mask actually holds.

Do I need to know Dart before starting this path?

Classes, generics, lists, maps and null safety, at least. If those are new, Coddy's Dart course takes you there first, free, and this path picks up where it ends.

Do I get a certificate for the Data Structures & Algorithms path?

Yes. Finish every step and you get one free certificate for the whole Data Structures & Algorithms path. It lists each course you finished on the way, and links each course's own certificate, so anyone can check every skill it names. You can add it to your LinkedIn profile. It is a certificate of completion from Coddy, not an accredited qualification.

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