DSA 75 Visual Roadmap

Step-by-step pattern progression path. Master each pattern in order from foundational pointer techniques to advanced dynamic programming.

Two Pointers

Attack the problem from two angles. Optimize O(n²) to O(n).

6 Problems

Attack the problem from two angles. Optimize O(n²) to O(n).

Two Sum II - Sorted Array Container With Most Water 3Sum Trapping Rain Water Move Zeroes Sort Colors

Sliding Window

Efficiently process contiguous subarrays and substrings.

5 Problems

Efficiently process contiguous subarrays and substrings.

Maximum Sum Subarray of Size K Longest Substring Without Repeating Longest Repeating Character Replacement Maximum Points from Cards Max Sum of Distinct Subarray of Size K

Stack

LIFO mastery — parentheses, monotonic stacks, and expression parsing.

7 Problems

LIFO mastery — parentheses, monotonic stacks, and expression parsing.

Valid Parentheses Min Stack Evaluate Reverse Polish Notation Daily Temperatures Largest Rectangle in Histogram Decode String Longest Valid Parentheses

Binary Search

Divide and conquer to achieve O(log n) search efficiency.

3 Problems

Divide and conquer to achieve O(log n) search efficiency.

Binary Search Koko Eating Bananas Search in Rotated Sorted Array

Intervals

Merge, insert, and process overlapping time ranges.

6 Problems

Merge, insert, and process overlapping time ranges.

Merge Intervals Insert Interval Non-overlapping Intervals Meeting Rooms Meeting Rooms II Min Arrows to Burst Balloons

Linked List

Pointer manipulation, cycle detection, and list reversal.

5 Problems

Pointer manipulation, cycle detection, and list reversal.

Linked List Cycle Remove Nth Node From End Reorder List Palindrome Linked List Swap Nodes in Pairs

Heap / Priority Queue

Efficient min/max element access for streaming and top-K problems.

4 Problems

Efficient min/max element access for streaming and top-K problems.

Kth Largest Element in a Stream K Closest Points to Origin Merge K Sorted Lists Find K Closest Elements

DFS — Trees

Recursion on tree structures: depth, paths, and validation.

6 Problems

Recursion on tree structures: depth, paths, and validation.

Maximum Depth of Binary Tree Path Sum Validate Binary Search Tree Diameter of Binary Tree Count Good Nodes in Binary Tree Path Sum II

BFS — Level Order

Layer-by-layer traversal for shortest paths and level processing.

5 Problems

Layer-by-layer traversal for shortest paths and level processing.

Binary Tree Right Side View Rotting Oranges 01 Matrix Binary Tree Zigzag Level Order Traversal Bus Routes

Graphs

Connectivity, topological sort, and cycle detection.

7 Problems

Connectivity, topological sort, and cycle detection.

Number of Islands Clone Graph Pacific Atlantic Water Flow Course Schedule Course Schedule II Surrounded Regions Graph Valid Tree

Backtracking

Explore all possibilities and prune invalid paths.

4 Problems

Explore all possibilities and prune invalid paths.

Subsets Combination Sum Generate Parentheses Word Search

Dynamic Programming

Optimal substructure meets overlapping subproblems.

7 Problems

Optimal substructure meets overlapping subproblems.

Longest Increasing Subsequence Unique Paths Decode Ways Word Break Maximal Square Counting Bits Maximum Profit in Job Scheduling

Greedy

Locally optimal choices that lead to globally optimal solutions.

3 Problems

Locally optimal choices that lead to globally optimal solutions.

Best Time to Buy and Sell Stock Jump Game Gas Station

Trie

Prefix tree for efficient string search and autocomplete.

2 Problems

Prefix tree for efficient string search and autocomplete.

Implement Trie (Prefix Tree)Search Suggestions System

Prefix Sum

Precompute once, then answer any range query in constant time.

2 Problems

Precompute once, then answer any range query in constant time.

Subarray Sum Equals K Count Vowels in Ranges

Matrices

In-place manipulation, spiral traversal, and grid transformations.

3 Problems

In-place manipulation, spiral traversal, and grid transformations.

Spiral Matrix Rotate Image Set Matrix Zeroes