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Zig

688 problems50 sections📅 2026 curriculum

Learn Zig by typing explicit, low-level code.

Type your way into Zig: explicit allocators, comptime metaprogramming, error unions and try, optionals, and slices with no hidden control flow. Each snippet is idiomatic Zig, and an AI tutor explains every line — why passing an allocator makes allocation visible, how comptime runs code at compile time — so Zig's no-surprises philosophy clicks as you type.

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Run Zig on your machine

1. Install the toolchain

brew install zig

2. Save your code as hello.zig, then compile & run

zig run hello.zig

Official install docs ↗

progress by section

1Fundamentals0/9start →

Hello, Zig const and var Functions Integer and float types Arrays if and switch while and for comptime constants defer

2Strings In Depth0/19start →

String literals Classify ASCII bytes Compare with mem.eql Find a single byte Iterate over bytes len counts bytes Multiline strings Strings are byte slices Prefix and suffix Format with an allocator Uppercase ASCII Format into a stack buffer Find a substring Slice by byte offset Split on a byte Split on a sequence Tokenize collapses gaps Concatenate with an allocator Join with a separator

3Values & References0/18start →

Address-of Pass by value copies Read-only pointers Dereference with .*Single-item pointers Pass by pointer Mutate through a pointer Optionals vs pointers Mutable slices Slices are fat pointers Pointer to a struct Swap through pointers Pointer to an array Optional pointers Return a pointer Methods that mutate Many-item pointers Sentinel-terminated pointers

4Slices & Arrays0/18Unlock →

Arrays have a fixed length Slice length Fill a slice First and last Open-ended ranges Slice a range Reverse in place Bulk copy Find an element A slice is pointer plus length Sort in place Subslice a slice Binary search Chunks of n Sentinel-terminated slices Stable sort Sort by a key Sliding windows

5Data structures0/10Unlock →

Fixed arrays Slices view arrays ArrayList basics AutoHashMap Structs with methods Tuples ArrayHashMap keeps order StringHashMap word count Tagged unions A generic stack

6Iterators0/20Unlock →

7Traits0/20Unlock →

8Generics0/15Unlock →

anytype parameter Generic function Two type parameters @TypeOf and @typeName comptime evaluation Generic default value Generic min over a slice Generic newtype wrapper Generic struct Generic sum over anything Generic tagged union Type parameterized by a length Generic with a key function Generic methods Reflection with @typeInfo

9Lifetimes0/20Unlock →

10Closures0/20Unlock →

11Pattern Matching0/20Unlock →

12Error Handling0/21Unlock →

13Option & Result0/21Unlock →

14Conversions0/15Unlock →

@as coercion @intFromBool Byte and character parseFloat parseInt Digit character to value @intFromEnum @floatFromInt @intFromFloat truncates Integer to string Narrow with @intCast Own a copy of a slice @enumFromInt @truncate keeps low bits @bitCast reinterprets bits

15Collection Conversions0/19Unlock →

Flatten nested slices Map keys to a slice Map values to a slice Pairs to a map Set to a sorted slice Slice to a double-ended list Slice to a set Slice to sorted-unique Boxing and unboxing Slice to a frequency map Map keys to a set Iterate a map in key order Map to a slice of pairs Two slices to a map Unique, keeping order Group a slice into a map Invert a map List to an owned slice A slice of tagged unions

16Math0/14Unlock →

Math constants Float functions Integer arithmetic min, max, clamp Rounding Average of a slice Logarithms & exp abs_diff & signum Trigonometry Bit math Comparing floats Euclidean div & mod hypot & atan2 Min/max of floats

17Encoding0/22Unlock →

18Random0/20Unlock →

19Data I/O0/18Unlock →

Parse CSV into rows Tab-separated values Build a CSV string Select one column CSV into a number matrix Split off the header Whitespace-separated matrix Read a data file Serialize records to CSV Skip blanks and comments Print an aligned table Serialize CSV to write out Write a matrix as text Append a row Parse key=value config Round-trip write then read Stream lines one at a time Drop unparseable rows

20Linear Algebra0/21Unlock →

21Text Processing0/16Unlock →

Word count Count occurrences Strip all whitespace Replace text Reverse word order Count vowels Zero-pad a number Pad and align Capitalize the first letter Character frequency Byte offset of each char Longest word Number the lines Title case Truncate with an ellipsis Levenshtein distance

22Date & Time0/12Unlock →

Duration arithmetic Duration units Elapsed since a start time Seconds to HH:MM:SS Time a block of work Scale a duration UNIX timestamp now Average duration Break a span into parts Deadline check Parse a clock string Throughput

23Memory0/12Unlock →

Free before scope end Swap two values Replace, keep the old Size and alignment Take, leave a default Arena allocation Build a value at comptime Borrow or own a copy Stack-only allocation Leak detection Initialize once Reinterpret with @ptrCast

24Modules0/20Unlock →

25Macros0/20Unlock →

26Testing0/20Unlock →

27Algorithms0/10Unlock →

Greatest common divisor Reverse a string Binary search Pseudo-random numbers Palindrome check Fibonacci with memoization Merge two sorted slices Fisher-Yates shuffle Two sum Quicksort

28Sorting Algorithms0/12Unlock →

Check if sorted Standard library sort Bubble sort Sort by a custom comparator Insertion sort Selection sort Counting sort Merge sort Shell sort Heapsort Quicksort in place Radix sort

29Expression Parsing0/6Unlock →

Evaluate postfix (RPN)Tokenize an expression Evaluate infix Recursive-descent calculator Right-associative power Shunting-yard

30Idioms0/10Unlock →

defer for cleanup if with optional capture Optionals and orelse Slices comptime blocks errdefer Error unions and try Labeled block as expression Tagged unions and switch while with optional capture

31OOP & Traits0/8Unlock →

Encapsulation Composition over inheritance Shared behavior Structural interfaces Dynamic polymorphism A printable type Static polymorphism Extend by composing a base

32Trait Objects0/14Unlock →

Default method on an interface An array of mixed variants Return one of several types Dispatch through an interface One fixed type vs many Store function pointers A slice of interfaces Static vs dynamic dispatch Composed interfaces An interface over borrowed data Recover the concrete type A handler registry Shared implementer on the heap A uniform vtable table

33Design Patterns0/14Unlock →

Lazy initialization Builder Factory method Singleton State machine Strategy Adapter Command Dependency injection Object pool Prototype Decorator Observer Actor

34Async0/3Unlock →

async/await were removed io.async and a Future Producer and consumer

35File I/O0/6Unlock →

Read a file Write a file Append to a file Read a file line by line Count lines helper Buffered writing

36Filesystem0/18Unlock →

Does a path exist?Copy a file Create nested directories Files vs directories Build a path List a directory Rename or move File metadata Path components Remove files and trees Write to a temp directory Change the extension Filter by extension Last modified time Absolute path Sorted listing Total size of a tree Walk the tree

37Networking0/16Unlock →

Parse the request line Route by path Classify an IP address Parse a socket address Bind an ephemeral port Build an HTTP response Read a line from a stream Resolve an address Shut down a connection TCP client + echo Receive timeout UDP receive UDP send A thread per connection TCP echo server Serve an HTTP response

38Concurrency0/7Unlock →

Spawn a thread Share data with a thread Atomic counter Fan out with futures Wait for a group of tasks A mutex-guarded counter Atomic builtins

39Unsafe & FFI0/14Unlock →

Dereference a pointer A function pointer @memcpy Export a function to C An extern struct Call a C function const and mutable pointers A volatile pointer Reinterpret the bits Address round-trip Many-item pointers A packed struct Reinterpret a pointer Slice from a pointer

40Commands0/14Unlock →

Command-line arguments Skip the program name Env var with a default Read an environment variable Current directory Iterate all env vars Set and remove a variable Path to this executable Exit with a code Pass env to a child Run a command Spawn and wait Command exit status Read all of stdin

41Array0/10Unlock →

Contains Duplicate Two Sum Best Time to Buy and Sell Stock Maximum Subarray Container With Most Water Find Minimum in Rotated Sorted Array Product of Array Except Self Maximum Product Subarray Search in Rotated Sorted Array 3Sum

42Binary0/5Unlock →

Missing Number Number of 1 Bits Counting Bits Reverse Bits Sum of Two Integers

43String0/10Unlock →

Valid Anagram Valid Palindrome Valid Parentheses Encode and Decode Strings Group Anagrams Longest Substring Without Repeating Characters Longest Repeating Character Replacement Longest Palindromic Substring Palindromic Substrings Minimum Window Substring

44Matrix0/4Unlock →

Rotate Image Set Matrix Zeroes Spiral Matrix Word Search

45Interval0/5Unlock →

Meeting Rooms Merge Intervals Insert Interval Non-overlapping Intervals Meeting Rooms II

46Linked List0/6Unlock →

Reverse Linked List Linked List Cycle Merge Two Sorted Lists Remove Nth Node From End Merge K Sorted Lists Reorder List

47Tree0/14Unlock →

Maximum Depth of Binary Tree Invert Binary Tree Same Tree Lowest Common Ancestor of a BST Binary Tree Level Order Traversal Subtree of Another Tree Implement Trie (Prefix Tree)Kth Smallest Element in a BST Validate Binary Search Tree Add and Search Word Construct Binary Tree from Preorder and Inorder Binary Tree Maximum Path Sum Serialize and Deserialize Binary Tree Word Search II

48Graph0/8Unlock →

Number of Connected Components Number of Islands Clone Graph Course Schedule Longest Consecutive Sequence Graph Valid Tree Alien Dictionary Pacific Atlantic Water Flow

49Heap0/3Unlock →

Kth Largest Element in an Array Top K Frequent Elements Find Median from Data Stream

50Dynamic Programming0/11Unlock →

Climbing Stairs House Robber Unique Paths Coin Change House Robber II Jump Game Combination Sum IV Decode Ways Longest Common Subsequence Longest Increasing Subsequence Word Break