DSAWithSwift - Complete Swift DSA Study Guide

A comprehensive, pattern-driven repository for mastering Data Structures and Algorithms using Swift. This project is designed as a modular, standalone library of 150+ common interview problems, categorized by algorithmic patterns rather than difficulty.

🚀 Key Features

• Pattern-Based Learning: Chapters organized by core concepts (Sliding Window, Two Pointers, Monotonic Stack, etc.).
• Standalone Implementations: Every problem file includes all necessary helper structures (ListNode, TreeNode, DSU) to run in isolation.
• Conceptual Documentation: Each topic includes a Concept.md file explaining the theory, Big O complexity, and when to apply the pattern.
• Clean & Documented: Code follows Swift's best practices with detailed headers and complexity analysis for every solution.
• Test-Ready: Integrated test cases at the end of each file for local verification.

🗺️ Recommended Study Path

To master these patterns effectively, we recommend following this hierarchical path. Each level builds the foundation for the next:

graph TD
    subgraph Phase 1: Linear Foundations
    A[Arrays & Strings] --> B[Linked Lists]
    B --> C[Stacks & Queues]
    end

    subgraph Phase 2: Algorithmic Logic
    C --> D[Two Pointers & Sliding Window]
    D --> E[Sorting & Searching]
    E --> F[Recursion & Backtracking]
    end

    subgraph Phase 3: Hierarchical Structures
    F --> G[Trees & BST]
    G --> H[Heaps & Priority Queues]
    G --> I[Tries]
    end

    subgraph Phase 4: Complex Networks
    H --> J[Graphs & Traversal]
    I --> J
    J --> K[Shortest Path & MST]
    K --> L[Greedy Patterns]
    end

    subgraph Phase 5: Advanced Optimization
    L --> M[Dynamic Programming]
    end

    style A fill:#f9f,stroke:#333,stroke-width:2px
    style M fill:#69f,stroke:#333,stroke-width:4px

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📂 Repository Structure

The repository follows a granular hierarchy for efficient navigation:

Category	Topics Included
Arrays	Sliding Window (Fixed/Variable), Two Pointers, Prefix Sum, Kadane's
Graphs	Traversal (BFS/DFS), Shortest Path (Dijkstra, Bellman-Ford, Floyd-Warshall), Spanning Trees (Kruskal, Prims), Union-Find (DSU)
Trees	BST, Path-based (Diameter, Max Path Sum), Traversals, Recursion Patterns
Heaps	Top K Elements, K-way Merge, Frequency Sorting, Greedy Selection
Stacks	Monotonic Stacks (Increasing/Decreasing), Histogram Pattern, Range & Span
Strings	Pattern Matching (KMP, Rabin-Karp, Z-Algorithm), Sliding Window
Recursion	Backtracking (Permutations, Subsets, Word Search), Divide & Conquer
Sorting	All Comparison & Non-Comparison (Radix, Counting, Bucket) Sorts

🛠️ How to Use

1. Study the Concept

Navigate to any topic folder and read the Concept.md. This provides the mental model required to solve problems in that category.

2. Run Implementations

Each file is a standalone Swift script. You can execute them directly via the terminal:

# Example: Running the Kruskal Algorithm implementation
swift Graphs/SpanningTree/Kruskal/KruskalAlgorithm.swift

📝 Example Output

When you run an implementation, it provides a clean output of the test cases:

Minimum Weight Sum (Kruskal): 19
Index of 4 in sorted array: 3
Maximal Rectangle Area: 6

📜 License

This project is licensed under the MIT License. See the LICENSE file for details.

📅 6-Month Study Guide

A structured roadmap to master Data Structures and Algorithms from scratch using this repository.

Tip

View the Complete 24-Week Roadmap: For a granular, week-by-week guide with missions and curated problems, check out the Detailed STUDY_PLAN.md.

Month	Focus Area	Key Patterns	Featured Problems
Month 1	Arrays & Basic Logic	Sliding Window, Two Pointers, Binary Search	TwoSumSorted.swift, LongestSubstringNoRepeat.swift, BinarySearchFindRange.swift
Month 2	Linear Data Structures	Linked Lists, Valid Parentheses, Monotonic Stack	ReverseLinkedList.swift, ValidParentheses.swift, NextGreaterElement.swift
Month 3	Hierarchical Structures	Trees, BST, LCA, Path Sums	DiameterOfBinaryTree.swift, ValidateBST.swift, LowestCommonAncestor.swift
Month 4	Heaps & Tries	Top K, Priority Queues, Prefix Matching	KthLargestElement.swift, MergeKSortedLists.swift, ImplementTrie.swift
Month 5	Graph Theory	BFS, DFS, Shortest Paths, Union-Find	MaxAreaOfIsland.swift, DijkstraAlgorithm.swift, RedundantConnection.swift
Month 6	Optimization & Greedy	Backtracking, Greedy Selection, MST	NQueens.swift, FractionalKnapsack.swift, KruskalAlgorithm.swift

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Created with ❤️ for the Swift Developer Community.