backtracking

Letter Combinations of a Phone Number

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

Generate Parentheses

Generate Parentheses requires generating all valid combinations of parentheses with given pairs using backtracking and s…

Sudoku Solver

Solve the Sudoku puzzle by filling empty cells while respecting Sudoku's rules using array scanning and backtracking.

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…

Unique Binary Search Trees II

Generate all structurally unique BSTs with values 1 to n using backtracking and recursive tree construction techniques.

Path Sum II

Find all root-to-leaf paths in a binary tree where the sum of node values equals a given target using DFS backtracking.

Word Ladder II

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

Palindrome Partitioning

Find all possible palindrome partitioning of a string using backtracking and dynamic programming.

Word Break II

Given a string and dictionary, return all possible sentences by adding spaces where each word is in the dictionary.

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.

Binary Tree Paths

Find all root-to-leaf paths in a binary tree using DFS and backtracking, constructing strings for each complete path eff…

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…

Count Numbers with Unique Digits

The problem asks to count numbers with unique digits from 0 to 10^n using dynamic programming, math, and backtracking te…

Binary Watch

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

Matchsticks to Square

The problem asks to determine if we can use matchsticks to form a square, exploring dynamic programming and backtracking…

Non-decreasing Subsequences

Return all possible non-decreasing subsequences with at least two elements from the input array, nums.

Target Sum

Target Sum requires counting all expressions from nums using '+' or '-' that evaluate exactly to the given target intege…

Beautiful Arrangement

The Beautiful Arrangement problem asks for the number of valid permutations of n integers satisfying specific divisibili…

Shopping Offers

Minimize the cost of purchasing items using available special offers with state transition dynamic programming.

24 Game

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

Stickers to Spell Word

Determine the minimum number of stickers needed to spell a target word using array scanning and hash lookups for efficie…

Partition to K Equal Sum Subsets

Determine if an integer array can be partitioned into k subsets where each subset sums to the same value using DP and ba…

Sliding Puzzle

Determine the minimum moves to solve a 2x3 sliding puzzle using BFS and state transition dynamic programming techniques …

Letter Case Permutation

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

All Paths From Source to Target

Find all paths in a directed acyclic graph (DAG) from source to target using depth-first search and backtracking.

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…

Smallest String Starting From Leaf

Determine the lexicographically smallest string from a leaf to root using binary-tree traversal and careful state tracki…

Number of Squareful Arrays

Count the number of squareful arrays from the given list of integers by checking adjacent pairs' sums for perfect square…

Letter Tile Possibilities

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

Brace Expansion II

Solve Brace Expansion II efficiently by using stack-based state management to generate all unique combinations of nested…

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 …

Maximum Score Words Formed by Letters

Calculate the highest total score by selecting words from a list using available letters, respecting individual letter s…

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.

Probability of a Two Boxes Having The Same Number of Distinct Balls

Compute the probability that two boxes contain the same number of distinct balls using careful combinatorial and DP meth…

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.

Distribute Repeating Integers

Determine if you can allocate integers to satisfy customer quantities using state transition dynamic programming techniq…

Construct the Lexicographically Largest Valid Sequence

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

Find Minimum Time to Finish All Jobs

Minimize the maximum working time of k workers by optimally assigning jobs, leveraging dynamic programming and bit manip…

Closest Dessert Cost

Find the closest dessert cost to a target by selecting from a list of base flavors and topping combinations using dynami…

Maximize Score After N Operations

Maximize the score after n operations by selecting pairs from the array and using their GCD with dynamic programming or …

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.

Maximum Compatibility Score Sum

Assign students to mentors to maximize total compatibility using state transition dynamic programming with bitmask optim…

Find Unique Binary String

Find a binary string of length n not in the input array using array scanning and hash lookup efficiently.

Minimum Number of Work Sessions to Finish the Tasks

Find the minimum number of work sessions needed to finish a set of tasks, considering task durations and session time.

Maximum Product of the Length of Two Palindromic Subsequences

Find two disjoint palindromic subsequences in a string to maximize the product of their lengths efficiently using dynami…

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…

Fair Distribution of Cookies

The problem focuses on fairly distributing cookies among children to minimize the maximum unfairness of the distribution…

Construct Smallest Number From DI String

Construct the lexicographically smallest string that fits the increasing and decreasing conditions of a given pattern.

Maximum Rows Covered by Columns

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

The Number of Beautiful Subsets

Count all non-empty subsets of an array where no two numbers have an absolute difference equal to k, using array scannin…

Find the Punishment Number of an Integer

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

Maximum Strength of a Group

Maximize the strength of a student group by carefully selecting students based on their scores, using dynamic programmin…

Partition String Into Minimum Beautiful Substrings

Partition a binary string into the fewest beautiful substrings using state transition dynamic programming and careful su…

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…

Minimum Time to Break Locks I

Solve the Minimum Time to Break Locks I problem using state transition dynamic programming to minimize the time to break…