Interview Prep: Algorithm Patterns

Master the patterns that appear in 90% of coding interviews.

Each pattern includes a generic template, recognition signals, complexity analysis, and curated LeetCode problems. Practice with our capstone exercises to build muscle memory.

Why Practice Algorithm Patterns?

Most coding interview problems are variations of a small set of patterns. Once you recognize the pattern, you know the template. Once you know the template, you can focus on adapting it to the specific problem instead of inventing solutions from scratch.

These patterns are not tricks to memorize. They are fundamental techniques that experienced programmers internalize through practice. Understanding WHY each pattern works is more valuable than memorizing code.

Array Patterns

Techniques for efficiently processing and searching arrays and sequences.

Two Pointers

Intermediate

Very CommonO(n)

The Two Pointers technique for sorted array problems. Covers the template, when to use it, and common interview problems like Two Sum II and Container With Most Water.

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Sliding Window (Fixed Size)

Intermediate

Very CommonO(n)

The fixed-size sliding window technique for subarray problems. Covers the template, "size k" signals, and problems like Maximum Average Subarray and Find All Anagrams.

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Sliding Window (Variable Size)

Intermediate

Very CommonO(n)

The variable-size sliding window technique for finding optimal subarrays. Covers the template, "longest/shortest" signals, and problems like Longest Substring Without Repeating Characters.

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Graph Patterns

Traversal and search algorithms for graph and tree structures.

BFS (Breadth-First Search)

Intermediate

Very CommonO(V + E)

Breadth-first search templates for shortest path, level-order traversal, and grid BFS. Learn when to use BFS vs DFS with LeetCode practice problems.

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DFS (Depth-First Search)

Intermediate

Very CommonO(V + E)

DFS templates for graph traversal, flood fill, cycle detection, and topological sort. Recursive and iterative approaches with LeetCode problems.

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Search Patterns

Binary search and its variations for efficient searching.

Binary Search

Beginner

Very CommonO(log n)

Binary search templates for exact match, lower/upper bound, rotated arrays, and binary search on the answer using monotonic predicates. Master O(log n) search.

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Practice Algorithm Patterns

Learn by doing. Our capstone exercises guide you through implementing each pattern step by step, building the muscle memory you need for interviews.

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