Preface

Fast Track

Master patterns, not problems.

This is an interview-focused roadmap. Every reasonable interview question is just a variation of a few core patterns. Master these foundations, and you'll stop memorizing code and start seeing solutions intuitively.

🚀

The Goal

Able to solve resonable interview questions ASAP.

Time Commitment

4-6 weeks (1-2 hours daily)

🎯

Who is this for?

⏰

Fast-Track Prep

You need to be interview-ready in weeks, not months, and can't afford to waste time on low-impact problems.
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Zero Frustration

Learn from patterns and answers directly. Skip the hours of pain—once you master the core patterns, solutions follow naturally.
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Anti-Grind Method

Master the underlying logic once. Stop the endless cycle of solving and memorizing thousands of individual LeetCode problems.
Part 1
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Part 1: Data Structures Basics

Weeks 1-2

Arrays & Linked Lists

Beginner
2 days
  • Array basics and circular array technique
  • Linked list principles & Two-pointer technique
  • Sequential vs linked storage analysis
  • O(1) insertion/deletion optimizations

Hash Tables

Beginner
1-2 days

Core Focus: Hash table principles and usage patterns like LinkedHashMap and ArrayHashMap.

Note: You can skip detailed collision resolution implementations.

Binary Trees

Critical Foundation
2-3 days
Crucial: All recursive algorithms are essentially tree traversals. Mastery here unlocks DFS, Backtracking, and DP.
  • Recursive & level-order traversal frameworks
  • N-ary trees & binary tree properties
  • DFS vs BFS decision matrix

Heaps & BSTs

Essential
1.5 days
  • BST: "Left smaller, right larger" search properties
  • Heap: Priority queues and O(log N) operations

Graphs Basics

Beginner
1 day
  • Adjacency list vs matrix representations
  • Standard DFS/BFS traversal templates
Part 2
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Part 2: Algorithm Patterns

Weeks 2-5

⭐

Mandatory Reading: Before diving into patterns, read the Framework Thinking for Learning DSA. It reveals the essence shared by all algorithms.

Linked List Techniques

Intermediate
2 days
  • Two-pointer technique framework (1 day)
  • Classic list problems & recursive operations (1 day)

Advanced Array Patterns

Intermediate
4-5 days
Key TechniquesBinary search, Sliding window, Two-pointers
SpecializedPrefix sums, Difference arrays, 2D traversal

Stacks & Queues

Intermediate
3 days
  • Monotonic stack/queue frameworks (Critical for "Next Greater Element" types)
  • Basic implementations and classic interview problems

Binary Tree Deep Dive

High Frequency
5-7 days
⚠️

Interview Success: This is the most crucial section. Spend extra time here.

Phase 1: Traversal vs Decomposition thinking models

Phase 2: Binary tree construction and serialization

Phase 3: Lowest common ancestor & tree diameter patterns

Graph Patterns

Intermediate
4 days
  • Topological Sort & Cycle Detection (Critical)
  • Union-Find (Kruskal's, Bipartite checks)
  • Dijkstra's Shortest Path Framework

Backtracking & DFS

Advanced
5-7 days

"The fallback solution for any difficult problem."

  • Standard Backtracking Template (Permutations, Subsets)
  • State management and "Choose-Explore-Unchoose" pattern
  • Grid DFS (Island problems)

Dynamic Programming

Advanced
7-10 days
Foundations

Memoization, State transition equations, Base cases

Sequence DPLIS, LCS, Edit Distance
Knapsack & Others0/1, Complete, Game Theory