Data structures and algorithms problems in C++ using STL

The Standard Template Library (STL) is a library for the C++ programming language. The STL provides many useful algorithms and containers. The Containers are objects that store data. We have taken the help of the following containers to solve mentioned problems:

vector, list, queue, priority_queue, stack, set, map, multimap, unordered_set, unordered_multiset, unordered_map, unordered_multimap

 
We have avoided using STL algorithms as the main purpose of these problems is to improve your coding skills and using in-built algorithms will do no good. Nevertheless, we have still used the following common algorithms at several places:

min, max, swap, sort, next_permutation, binary_search, rotate, reverse

Priority Queue (Heap):

• Min Heap and Max Heap Implementation in C++Beginner
• Find k’th largest element in an arrayMedium
• Sort a k-sorted arrayMedium
• Find k’th smallest element in an arrayMedium
• Find the smallest range with at least one element from each of the given listsHard
• Merge M sorted lists each containing N elementsHard
• Merge M sorted lists of variable lengthHard
• Huffman Coding Compression AlgorithmHard
• External Merge Sort AlgorithmHard

Graphs:

• Graph Implementation in C++ using STLBeginner
• Breadth-First Search (BFS) – Iterative and Recursive ImplementationMedium
• Depth First Search (DFS) – Iterative and Recursive ImplementationMedium
• Disjoint–Set Data Structure (Union–Find Algorithm)Medium
• Kruskal’s Algorithm for finding Minimum Spanning TreeHard
• Single-Source Shortest Paths – Dijkstra’s AlgorithmMedium
• Graph Coloring ProblemMedium
• Print all Hamiltonian paths present in a graphHard
• Kahn’s Topological Sort AlgorithmMedium
• Compute the least cost path in a weighted digraph using BFSMedium

Array:

• Rearrange an array with alternate high and low elementsMedium
• Find a pair with the given sum in an arrayEasy
• Find equilibrium index of an arrayEasy
• Find majority element (Boyer–Moore Majority Vote Algorithm)Easy
• Print all subarrays with 0 sumMedium
• Find maximum length subarray having a given sumMedium
• Find maximum length subarray having an equal number of 0’s and 1’sMedium
• Find all distinct combinations of a given length – IMedium
• Find all distinct combinations of a given length – IIMedium
• Find all distinct combinations of a given length with repetition allowedMedium
• Merging Overlapping IntervalsMedium
• Find minimum platforms needed to avoid delay in the train arrivalMedium
• Longest Increasing Subsequence ProblemHard
• Iterative Implementation of QuicksortMedium
• Sort elements by their frequency and indexMedium
• Sort an array based on order defined by another arrayMedium
• Find a triplet with the given sum in an arrayMedium
• 4–Sum Problem | Quadruplets with a given sumMedium
• Binary Search Algorithm – Iterative and Recursive ImplementationEasy
• Find the peak element in an arrayMedium
• Activity Selection ProblemEasy
• Job Sequencing Problem with DeadlinesMedium
• Maximum Product Subset ProblemEasy
• Find pairs with difference k in an array | Constant Space SolutionMedium
• Find pairs with difference k in an arrayEasy
• Quickselect AlgorithmMedium
• Check if a subarray with 0 sum exists or notMedium
• 4–Sum Problem | Quadruplets with a given sumMedium
• Print all distinct subsets of a given setHard
• K–Partition Problem | Printing all partitionsHard
• 3–Partition ProblemMedium
• 3–partition problem extended | Printing all partitionsHard
• Find the frequency of each element in a sorted array containing duplicatesEasy
• Replace each array element by its corresponding rankEasy
• Group elements of an array based on their first occurrenceMedium
• Find all symmetric pairs in an array of pairsMedium
• Find the count of distinct elements in every subarray of size kMedium
• Print all subarrays of an array having distinct elementsMedium
• Find ways to calculate a target from elements of the specified arrayMedium
• Find the minimum index of a repeating element in an arrayEasy
• Check if an array is formed by consecutive integersMedium
• Find two non-overlapping pairs having the same sum in an arrayMedium
• Find two numbers with maximum sum formed by array digitsEasy
• Count distinct absolute values in a sorted arrayMedium
• Find subarrays with a given sum in an arrayMedium
• Find surpasser count for each array elementHard
• Find the maximum absolute difference between the sum of two non-overlapping subarraysHard
• Print all combinations of numbers from 1 to n having sum nMedium
• Find an index of the maximum occurring element with equal probabilityEasy

Matrix:

• Find all occurrences of the given string in a character matrixHard
• Flood Fill AlgorithmMedium
• Count number of islandsMedium
• Find all paths from the first cell to the last cell of a matrixMedium
• Find the probability that a person is alive after taking n steps on an islandMedium
• Find the path from source to destination in a matrix that satisfies given constraintsMedium
• Find all common elements present in each row of a matrixMedium
• Construct a binary tree from an ancestor matrixHard
• Find common elements present in all rows of a matrixMedium
• Find the shortest distance of every cell from a landmine inside a mazeHard
• Find duplicate rows in a binary matrixMedium

Strings:

• Check if a string is a rotated palindrome or notMedium
• Check if a repeated subsequence is present in a string or notHard
• Check if strings can be derived from each other by circularly rotating themEasy
• Determine whether two strings are anagram or notEasy
• Find all binary strings that can be formed from a wildcard patternMedium
• Find all interleaving of given stringsEasy
• Isomorphic StringsMedium
• Find all possible palindromic substrings of a stringHard
• Find all possible combinations of words formed from the mobile keypadHard
• Find all possible combinations by replacing given digits with characters of the corresponding listHard
• >Find all words that follow the same order of characters as given patternMedium
• Find first k non-repeating characters in a string in a single traversalMedium
• Group anagrams together from a list of wordsMedium
• Reverse text without reversing individual wordsMedium
• Find the longest substring of a string containing k distinct charactersHard
• Find all palindromic permutations of a stringMedium
• Find all substrings of a string that are a permutation of another stringMedium
• Find the longest substring of a string containing distinct charactersMedium
• Find all permutations of a string in C++ (Using Backtracking and STL)Hard
• Find all lexicographically next permutations of a string sorted in ascending orderHard
• Lexicographically Minimal String RotationMedium
• Find all n-digit binary numbers with k-bits set where k ranges from 1 to nHard
• Generate binary numbers between 1 to n using a queueEasy
• Lexicographic rank of a stringHard
• Shortest Superstring ProblemHard
• Check if a string is interleaving of two other given stringsMedium
• Iterative approach to finding permutations of a stringHard
• std::next_permutation | Overview and Implementation in C++Medium
• std::prev_permutation | Overview and Implementation in C++Medium
• Implementation of KMP AlgorithmHard
• Construct the longest palindrome by shuffling or deleting characters from a stringMedium
• Determine whether the characters of a string follow a specified order or notMedium
• Determine whether a string matches with a given patternHard

Binary Tree:

• Check if two binary trees are identical or notEasy
• Calculate the height of a binary treeEasy
• Delete a binary treeEasy
• Level order traversal of a binary treeEasy
• Spiral order traversal of a binary treeMedium
• Reverse level order traversal of a binary treeEasy
• Print all nodes of a perfect binary tree in a specific orderHard
• Print left view of a binary treeEasy
• Print bottom view of a binary treeMedium
• Print top view of a binary treeMedium
• Find the next node at the same level as the given node in a binary treeMedium
• Check if a binary tree is a complete binary tree or notMedium
• Determine whether a binary tree is a subtree of another binary treeMedium
• Postorder Tree TraversalMedium
• Preorder Tree TraversalMedium
• Inorder Tree TraversalMedium
• Find ancestors of a given node in a binary treeMedium
• Find the vertical sum of a binary treeHard
• Perform vertical traversal of a binary treeMedium
• Find the diagonal sum of a binary treeMedium
• Print diagonal traversal of a binary treeMedium
• Print corner nodes of every level in a binary treeEasy
• Print right view of a binary treeMedium
• Compute the maximum number of nodes at any level in a binary treeEasy
• Build a binary tree from a parent arrayHard
• Find a pair with the given sum in a BSTEasy
• Construct a binary tree from an ancestor matrixHard
• Iteratively print the leaf to root path for every leaf node in a binary treeMedium

Dynamic Programming:

• Introduction to Dynamic ProgrammingBeginner
• Longest Common Subsequence ProblemMedium
• Longest Common Subsequence | Finding all LCSHard
• Longest Common Subsequence of k–sequencesMedium
• Longest Palindromic Subsequence using Dynamic ProgrammingMedium
• Longest Repeated Subsequence ProblemMedium
• Shortest Common Supersequence ProblemMedium
• Find the longest sequence formed by adjacent numbers in the matrixMedium
• Count the number of paths in a matrix with a given cost to reach the destination cellMedium
• 0–1 Knapsack ProblemMedium
• Subset Sum Problem – Dynamic Programming SolutionMedium
• Minimum Sum Partition ProblemHard
• Coin Change ProblemHard
• Find optimal cost to construct a binary search treeHard
• Maximum Length Snake SequenceMedium
• Check if a string is interleaving of two other given stringsMedium
• Find ways to calculate a target from elements of the specified arrayMedium

Linked List:

• Detect cycle in a linked list (Floyd’s Cycle Detection Algorithm)Easy
• Remove duplicates from a linked list in a single traversalEasy
• Remove duplicates from a linked list in a single traversalEasy
• Convert a multilevel linked list to a singly linked listMedium

Miscellaneous:

• C++ Implementation of Trie Data StructureBeginner
• Memory Efficient Implementation of Trie in C++ – Insert, Search and DeleteBeginner
• Generate the power set of a given setMedium
• Find numbers represented as the sum of two cubes for two different pairsMedium
• Traverse a given directory using BFS and DFS in JavaEasy