Master 49+ Essential Patterns

Learn the fundamental patterns that solve 90% of coding interview problems. Each pattern includes detailed explanations, key insights, and real company problems.

49+
Essential Patterns
500+
Practice Problems
100+
Top Companies
90%
Problem Coverage
Array & String Patterns

Two Pointers

Use two pointers to solve problems efficiently

Easy

Key Concepts:

Sorted arraysPalindromesPair finding

Asked by:

GoogleAmazonMicrosoft
25 problems
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Sliding Window

Maintain a window of elements to find optimal solutions

Medium

Key Concepts:

Subarray problemsFixed/Variable windowOptimization

Asked by:

FacebookAppleNetflix
20 problems
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Fast & Slow Pointers

Detect cycles and find middle elements

Medium

Key Concepts:

Cycle detectionLinked listsArray problems

Asked by:

LinkedInUberTwitter
15 problems
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Merge Intervals

Merge overlapping intervals efficiently

Medium

Key Concepts:

Interval schedulingOverlap detectionSorting

Asked by:

GoogleAmazonMicrosoft
12 problems
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Tree & Graph Patterns

Tree Traversal

Navigate trees using DFS and BFS techniques

Easy

Key Concepts:

Inorder/Preorder/PostorderLevel orderPath problems

Asked by:

GoogleFacebookAmazon
30 problems
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Binary Search Tree

Leverage BST properties for efficient solutions

Medium

Key Concepts:

ValidationConstructionOptimization

Asked by:

MicrosoftAppleSalesforce
18 problems
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Graph Traversal

Explore graphs using DFS and BFS

Medium

Key Concepts:

Connected componentsPath findingCycle detection

Asked by:

AmazonGoogleFacebook
22 problems
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Topological Sort

Order elements based on dependencies

Hard

Key Concepts:

Course schedulingBuild systemsDependency resolution

Asked by:

GoogleMicrosoftUber
10 problems
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Dynamic Programming

Linear DP

Solve problems with linear recurrence relations

Medium

Key Concepts:

1D problemsFibonacci variantsOptimization

Asked by:

GoogleAmazonMicrosoft
25 problems
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2D DP

Handle 2D grid and matrix problems

Hard

Key Concepts:

Grid traversalString matchingPath counting

Asked by:

FacebookGoogleAmazon
20 problems
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Knapsack Variants

Optimize resource allocation problems

Hard

Key Concepts:

0/1 KnapsackUnboundedMulti-dimensional

Asked by:

AmazonMicrosoftGoogle
15 problems
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Longest Common Subsequence

Find optimal subsequences and substrings

Medium

Key Concepts:

String problemsEdit distanceAlignment

Asked by:

GoogleFacebookAmazon
12 problems
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Searching & Sorting

Binary Search

Efficiently search in sorted arrays

Easy

Key Concepts:

Search spaceRotated arraysPeak finding

Asked by:

GoogleAmazonMicrosoft
20 problems
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Modified Binary Search

Adapt binary search for complex scenarios

Medium

Key Concepts:

Search in rotated arraysFind boundaries2D search

Asked by:

FacebookGoogleAmazon
18 problems
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Sorting Algorithms

Implement and optimize sorting techniques

Easy

Key Concepts:

Quick sortMerge sortCustom comparators

Asked by:

MicrosoftAppleGoogle
15 problems
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Advanced Patterns

Backtracking

Explore all possible solutions systematically

Hard

Key Concepts:

PermutationsCombinationsConstraint satisfaction

Asked by:

GoogleFacebookAmazon
25 problems
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Greedy Algorithms

Make locally optimal choices

Medium

Key Concepts:

Activity selectionHuffman codingMinimum spanning tree

Asked by:

AmazonMicrosoftGoogle
18 problems
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Bit Manipulation

Solve problems using bitwise operations

Medium

Key Concepts:

XOR propertiesBit maskingPower of 2

Asked by:

GoogleFacebookAmazon
15 problems
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Union Find

Efficiently handle disjoint set operations

Hard

Key Concepts:

Connected componentsCycle detectionPath compression

Asked by:

GoogleAmazonFacebook
12 problems
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How to Master These Patterns

Follow our proven approach to pattern mastery

1

Understand the Pattern

Study the core technique and identify when to apply it. Learn the underlying principles and common variations.

2

Practice Systematically

Start with easy problems and gradually increase difficulty. Focus on implementation details and edge cases.

3

Apply to New Problems

Test your understanding by solving variations and mixed problems. Build pattern recognition skills through repetition.

Ready to Master These Patterns?

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