Backtracking Masterclass | All Variants Explained | Subsets, Permutations, N-Queens, Sudoku

Lecture Resources https://github.com/Tiwarishashwat/Java-Plus-DSA-Placement-Course/tree/main/Lecture-100%20-%20Backtracking In this video, we cover Backtracking in depth and solve all major variants that are frequently asked in coding interviews and competitive programming. Backtracking is one of the most important recursion-based techniques, and mastering it unlocks solutions to dozens of classic problems. 🧠 What You Will Learn in This Video 🔹 Core Backtracking Concept Decision Tree & Choice Diagram Choose → Explore → Unchoose pattern When to use backtracking vs recursion Time & space complexity intuition 🔹 Problems Covered (All Variants) 📌 Subsets Subsets – I Subsets – II (handling duplicates) 📌 Permutations Permutations – I Permutations – II (duplicates allowed) 📌 String Backtracking Letter Combinations of a Phone Number Generate Parentheses 📌 Combination Problems Combination Sum – I Combination Sum – II 📌 Classical Backtracking Problems N-Queens Problem Sudoku Solver Palindrome Partitioning ⚙️ Common Backtracking Patterns Covered Include / Exclude Pick / Not Pick Swap-based recursion Path building with backtracking Constraint checking Pruning invalid branches ⏱️ Why Backtracking is Important ✔ Appears heavily in FAANG interviews ✔ Foundation for: DFS on grids Constraint satisfaction problems Recursion tree visualization Advanced search problems Timestamp: 0:00 - Backtracking 3:42 - Subsets 12:08 - Subsets -2 20:06 - Permutations 30:43 - Permutations -2 44:43 - Letter Combination of a phone number 57:10 - Generate Parentheses 1:12:22 - Combination Sum 1:26:19 - Combination Sum -2 1:36:27 - N Queen 1:58:03 - Sudoku Solver 2:22:49 - Palindrome Partitioning 2:34:08 - Outro