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Swift's standard library gives you Array, Dictionary and Set, and stops there: no queue, heap, linked list or tree. This path has you build each one in Swift, with classes for nodes and weak for the links that point back, 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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23 free certificates along the pathEach step is a set of existing Coddy courses, and every Start button opens them in Swift. The three courses not taught in Swift yet are listed after the steps.
Array makes a good stack and a slow queue, and what Dictionary does for you.Startweak earns its place, and the heap you write here is the one the graph step needs.Startsorted(by:) takes a closure such as { $0 > $1 }; after this step, you can write the algorithm on the other side of that call.Startindirect enum, a type allowed to contain itself, and Swift makes no promise of tail-call optimization, so a recursion deep enough crashes with a stack overflow instead of running forever. Dynamic programming and bit manipulation are listed after the steps, since they are taught in Python and C++.StartDedicated page&+, &- and &*.StartWrite real code, query databases, build websites, and master AI prompts. Our interactive lessons cover every skill modern developers need.
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A variable is a named container that stores a value you can reference later in your program.
In Python, you create one by writing the name, an equals sign, then the value you want to store.
The value can change over time - reassigning the name simply points it to a new value.
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Add to LinkedInDeque and Heap, reads differently once you have.Array, Dictionary and Set are value types with copy-on-write, so passing one around is cheap until someone changes it. A tree node cannot work that way: it has to be a class, or an indirect enum, and a parent pointer has to be weak, or ARC never frees the cycle. Data structures are where Swift's memory model stops being theory.&, |, ^, ~, << and >>.Comparable and Hashable, and optionals make a node whose next may be nil explicit in its type, and the compiler checks every use. Two things are worth knowing early: the standard library is thin, so you write your own queue and heap; and collections are values, so assigning an array to a new variable and changing it leaves the original alone, which surprises people coming from Java or JavaScript.Array is a dynamic array and a stack, with append and popLast(); Dictionary and Set are hash tables. That is the whole standard library. Apple's open-source swift-collections package adds Deque, Heap, OrderedSet and OrderedDictionary; the linked list, the tree, the trie and the graph you write yourself, in steps one and two.indirect enum also works, for trees you never change in place. The catch is ARC: a parent pointer must be weak, or parent and child keep each other alive and the tree is never freed.removeFirst(): on an Array it shifts every remaining element, so each dequeue is O(n). Keep a head index and advance it, or use two arrays: push onto an inbox, pop from an outbox, and refill the outbox by reversing the inbox when it runs empty. Both make dequeueing amortized O(1). swift-collections' Deque does it for you, and step one has you build a queue yourself.Dictionary, and Swift integers carry nonzeroBitCount and trailingZeroBitCount, which do in one property what a C++ bit trick does by hand.