Backtracking — Simple English

21 lessons · Data Structures & Algorithms · Simple English · Beginner Friendly

01 Backtracking: Building Solutions One Step at a TimeFree Backtracking: Trying Every Path Until One Works Imagine you are solving a maze. You walk down a path, and if you hit a d… 02 The Key Components of BacktrackingFree The Key Components of Backtracking Backtracking is a way of solving problems by trying things out. You make a choice, se… 03 Implementing Backtracking with Recursive Function CallsFree Implementing Backtracking with Recursion Backtracking is a way of solving problems by trying one choice at a time. When … 04 The Unconditional Enumeration Pattern (Backtracking)🔒 The Unconditional Enumeration Pattern Some problems do not have just one answer. They have many answers, and our job is … 05 Unconditional Enumeration: Generating All Subsets with Backtracking🔒 Unconditional Enumeration: Building Every Possible Subset What is unconditional enumeration? Sometimes a problem asks yo… 06 Generating All Subsets (The Power Set)🔒 Generating All Subsets (The Power Set) Imagine you have a small group of items, and you want to list every possible grou… 07 Case Transformations: Making All Upper/Lowercase Combinations of a String🔒 Case Transformations Imagine you have a word, and you are allowed to change each letter to either small (lowercase) or b… 08 Number Sequence: Building All Sequences of Length n Using Numbers 1 to k🔒 Number Sequence: Listing Every Possible Combination Imagine you have a small lock with a few wheels. Each wheel can show… 09 Phone Letter Combinations: Turning Digits into Words🔒 Phone Letter Combinations Think back to old mobile phones, the kind with physical number buttons. Each number button als… 10 Conditional Enumeration: Exploring Every Path When Each Choice Depends on the Last🔒 Conditional Enumeration Imagine you are building a sentence one word at a time. The word you pick first changes which wo… 11 Conditional Enumeration: Building Solutions One Choice at a Time🔒 Conditional Enumeration: Building Solutions One Choice at a Time Imagine you are walking through a maze where, at every … 12 Generate All Valid Parentheses with n Pairs🔒 Generate All Valid Parentheses This is a classic problem that teaches you a powerful technique called backtracking. Let'… 13 Target Sum Combinations: Finding All Ways to Reach a Number🔒 Target Sum Combinations Imagine you have a small set of coin values, and you want to make an exact amount of money. You … 14 Generate All Valid IP Addresses From a String of Digits🔒 Generate All Valid IP Addresses Imagine someone hands you a long string of digits, like 25525511235, and asks: "What are… 15 String Permutations: Finding Every Possible Arrangement🔒 String Permutations Imagine you have three letters: A, B, and C. How many different ways can you arrange them in a row? … 16 The Backtracking Search Pattern: How to Try, Check, and Undo🔒 The Backtracking Search Pattern What problem are we solving? Imagine you are standing at the entrance of a giant maze. Y… 17 The Backtracking Search Pattern: Solving a Rat in a Maze🔒 The Backtracking Search Pattern Imagine you are standing at the entrance of a hedge maze. You don't have a map. So you d… 18 Rat in a Maze: Finding a Path Out🔒 Rat in a Maze: Finding a Path Out Imagine a small grid of rooms, like a checkerboard. A rat starts in the top-left room … 19 Word Search on a Grid: Finding a Word in a 2D Board🔒 Searching for a Word in a Grid of Letters Imagine a small crossword-style grid filled with single letters. You are given… 20 The N-Queens Puzzle: Placing Queens So None Attack🔒 The N-Queens Puzzle Imagine you have a chessboard. In chess, the queen is the most powerful piece. She can move and atta… 21 Solving Sudoku: The Problem and Its Rules🔒 Solving Sudoku: The Problem and Its Rules Sudoku is a famous number puzzle. Before we write any code to solve it, we fir…