backtracking pruning Pattern

Letter Combinations of a Phone Number

Generate all letter combinations a digit string can represent using backtracking with pruning, leveraging hash table map…

Combination Sum

Find all unique combinations of numbers from a distinct array that sum to a target using controlled backtracking search.

Combination Sum II

Find all unique combinations of numbers that sum to a target using backtracking with careful pruning to avoid duplicates…

Permutations

Generate all possible orderings of a distinct integer array using backtracking search with careful pruning to avoid dupl…

Permutations II

Generate all unique permutations of an array containing duplicates using backtracking and pruning to avoid repeated sequ…

N-Queens

Solve the N-Queens problem using backtracking with pruning, exploring all valid board placements while avoiding conflict…

N-Queens II

Solve the N-Queens II problem using backtracking with pruning to efficiently count all valid placements for n queens on …

Combinations

Generate all combinations of k numbers from the range [1, n] using backtracking and pruning.

Subsets

Generate all subsets of a set of unique integers using backtracking with pruning to avoid duplicates.

Word Search

Solve Word Search with backtracking by exploring adjacent cells to match a target word in a grid.

Gray Code

Generate an n-bit Gray Code sequence using backtracking with pruning and bit manipulation techniques.

Subsets II

Subsets II problem asks to generate unique subsets from an array with possible duplicates using backtracking search with…

Restore IP Addresses

Restore all valid IP addresses from a string using backtracking with pruning, avoiding invalid segments or leading zeros…

Word Ladder II

Find all shortest transformation sequences from beginWord to endWord using a dictionary, leveraging backtracking search …

Word Search II

Solve the Word Search II problem using backtracking with pruning to find all words on a board of characters.

Combination Sum III

Find all unique combinations of k numbers adding to n using efficient backtracking with pruning in arrays.

Expression Add Operators

Expression Add Operators is solved with backtracking that builds multi-digit operands and tracks multiplication preceden…

Remove Invalid Parentheses

Remove the minimum number of invalid parentheses to generate all possible valid strings efficiently using backtracking a…

Additive Number

Additive Number is solved by trying the first two splits, then pruning aggressively while verifying each required sum in…

Binary Watch

Binary Watch involves generating possible times on a binary watch given a number of turned-on LEDs.

24 Game

Solve the 24 Game by arranging four card numbers using arithmetic operators and parentheses to reach exactly 24 efficien…

Letter Case Permutation

Letter Case Permutation involves generating all possible strings by changing the case of each letter in a given string.

Ambiguous Coordinates

Find all valid 2D coordinate possibilities for an ambiguous input string using backtracking and pruning techniques.

Split Array into Fibonacci Sequence

This problem challenges you to split a string into a Fibonacci-like sequence using backtracking and pruning.

Largest Time for Given Digits

Given four digits, determine the latest valid 24-hour time possible using each digit exactly once with backtracking.

Numbers With Same Consecutive Differences

Generate all n-digit numbers where consecutive digits differ by k using efficient backtracking and BFS techniques.

Unique Paths III

Solve the Unique Paths III problem using backtracking search with pruning to count 4-directional paths covering all empt…

Letter Tile Possibilities

Compute all unique non-empty sequences from given letter tiles using backtracking search with pruning efficiently.

Path with Maximum Gold

Find the path with the maximum gold in a grid with backtracking and pruning techniques to maximize the gold collected.

Circular Permutation in Binary Representation

Generate a circular permutation from a range of numbers using backtracking and bit manipulation.

Maximum Length of a Concatenated String with Unique Characters

Find the maximum length of a concatenated string from an array with all unique characters using backtracking search with…

Tiling a Rectangle with the Fewest Squares

Tiling a Rectangle with the Fewest Squares problem asks for the minimum number of squares required to cover a rectangle …

Iterator for Combination

Implement an iterator that generates all combinations of a given length using efficient backtracking with pruning.

Verbal Arithmetic Puzzle

Check if a verbal arithmetic equation can be solved using a valid digit-letter mapping.

The k-th Lexicographical String of All Happy Strings of Length n

Given n and k, find the k-th lexicographical happy string of length n using backtracking search with pruning.

Split a String Into the Max Number of Unique Substrings

Maximize unique substrings in a string using backtracking with pruning and hash tables to track substrings.

Maximum Number of Achievable Transfer Requests

Find the maximum number of achievable transfer requests between buildings with constraints on net employee transfers.

Construct the Lexicographically Largest Valid Sequence

Construct the Lexicographically Largest Valid Sequence problem involves finding the largest sequence with backtracking a…

Splitting a String Into Descending Consecutive Values

Check if a string of digits can be split into descending consecutive values where the difference between them is 1.

Sum of All Subset XOR Totals

Compute the sum of all subset XOR totals using a backtracking search with pruning for arrays of small size.

Longest Subsequence Repeated k Times

Find the longest subsequence repeated k times in a string using backtracking search with pruning.

Count Number of Maximum Bitwise-OR Subsets

Determine the number of non-empty subsets that achieve the maximum bitwise OR using efficient backtracking and pruning s…

Next Greater Numerically Balanced Number

Find the smallest numerically balanced number greater than a given integer using backtracking search and pruning.

Number of Valid Move Combinations On Chessboard

Given a set of pieces on a chessboard, calculate the number of valid move combinations without overlap using backtrackin…

Maximum Path Quality of a Graph

Calculate the maximum path quality in a graph using backtracking and pruning to optimize node visits within time limits …

Maximum Good People Based on Statements

Determine the maximum number of good people in a group given mutual statements, using precise backtracking with pruning.

Maximum Split of Positive Even Integers

Determine the largest set of unique positive even integers that sum to a given finalSum using backtracking and greedy se…

Maximum Points in an Archery Competition

In the "Maximum Points in an Archery Competition" problem, Bob aims to maximize his score while respecting Alice's arrow…

Maximum Rows Covered by Columns

Select exactly numSelect columns from a binary matrix to maximize rows where all ones are covered efficiently using back…

Find the Punishment Number of an Integer

Find the punishment number of a given integer using backtracking search with pruning.

Generate Binary Strings Without Adjacent Zeros

Generate all binary strings of length n without adjacent zeros using backtracking search with pruning for efficient enum…

Smallest Divisible Digit Product II

Find the smallest zero-free number at least as large as num whose digits multiply to a product divisible by t using care…