🚀 The 80/20 DSA Interview Playbook

This is not a list of 500 random problems. This is the highly curated, zero-BS collection of the exact Data Structures & Algorithmic patterns that top tech companies (Microsoft, Amazon, Google, Meta, Apple) actually test in their technical rounds.

🛑 STEP 1: The Core Foundation (Do This First)

Before you begin grinding LeetCode, you need to make sure your core logic and data structure fundamentals are rock solid. If your foundational logic is weak, you will struggle to recognize these patterns during a live interview.

Before diving into the patterns below, it is highly recommended that you brush up on your core logic using Microsoft's official, 100% free developer training hub.

👉 Access the Official Microsoft Developer Training Hub Here (DSA Fundamentals & Logic)

(Do not skip this step if your core fundamentals are rusty. Top companies care more about your underlying logic than your ability to memorize LeetCode solutions.)

🧠 STEP 2: The Core DSA Patterns (The 80/20 Rule)

1. Sliding Window

• Maximum Average Subarray I (Easy)
• Longest Substring Without Repeating Characters (Medium)
• Longest Repeating Character Replacement (Medium)
• Max Consecutive Ones III (Medium)
• Fruit Into Baskets (Medium)
• Minimum Window Substring (Hard)
• Sliding Window Maximum (Hard)

2. Two Pointers

• Valid Palindrome (Easy)
• Two Sum II - Input Array Is Sorted (Medium)
• Remove Duplicates from Sorted Array (Easy)
• 3Sum (Medium)
• 4Sum (Medium)
• Container With Most Water (Medium)
• Sort Colors (Medium)
• Trapping Rain Water (Hard)

3. Fast & Slow Pointers

• Linked List Cycle (Easy)
• Middle of the Linked List (Easy)
• Palindrome Linked List (Easy)
• Find the Duplicate Number (Medium)
• Linked List Cycle II (Medium)
• Reorder List (Medium)

4. Merge Intervals

• Merge Intervals (Medium)
• Insert Interval (Medium)
• Non-overlapping Intervals (Medium)

• Minimum Number of Arrows to Burst Balloons (Medium)

5. Binary Search (Modified)

• Binary Search (Easy)
• Search Insert Position (Easy)
• Find First and Last Position of Element in Sorted Array (Medium)
• Search in Rotated Sorted Array (Medium)
• Find Minimum in Rotated Sorted Array (Medium)
• Search a 2D Matrix (Medium)
• Koko Eating Bananas (Medium)

🌳 STEP 3: Advanced Structures

6. Tree / Graph BFS

• Binary Tree Level Order Traversal (Medium)
• Binary Tree Right Side View (Medium)
• Binary Tree Zigzag Level Order Traversal (Medium)
• Rotting Oranges (Medium)
• Populating Next Right Pointers in Each Node (Medium)
• Word Ladder (Hard)

7. Tree / Graph DFS

• Maximum Depth of Binary Tree (Easy)
• Invert Binary Tree (Easy)
• Diameter of Binary Tree (Easy)
• Lowest Common Ancestor of a Binary Tree (Medium)
• Number of Islands (Medium)
• Max Area of Island (Medium)
• Course Schedule (Medium)
• Course Schedule II (Medium)

8. Subsets / Backtracking

• Subsets (Medium)
• Subsets II (Medium)
• Permutations (Medium)
• Combination Sum (Medium)
• Word Search (Medium)
• Palindrome Partitioning (Medium)
• N-Queens (Hard)

9. Top K Elements (Heaps)

• Kth Largest Element in an Array (Medium)
• Top K Frequent Elements (Medium)
• K Closest Points to Origin (Medium)
• Merge k Sorted Lists (Hard)
• Find Median from Data Stream (Hard)

10. Dynamic Programming (1D & 2D)

• Climbing Stairs (Easy)
• Min Cost Climbing Stairs (Easy)
• House Robber (Medium)
• Coin Change (Medium)
• Longest Increasing Subsequence (Medium)
• Longest Common Subsequence (Medium)
• Unique Paths (Medium)
• Word Break (Medium)

--- Tranlated By Open Ai Tx | Last indexed: 2026-07-05 ---