Top 100 Data Structures and Algorithms (DSA)

Top 100 Data Structure and Algorithm Questions

PrepInsta Data Structures & Algorithms

PrepInsta Data Structures & Algorithms

Top 100 Data Structures and Algorithms – Data Structures and Algorithms (DSA) form the foundation of efficient programming. A data structure is a way of organizing and storing data so it can be accessed and modified easily. An algorithm is a set of step-by-step instructions used to solve a specific problem or perform a task.

Below you will find all the important Data Structures code that are important for you to learn DSA Preparation for Placements and College examinations and cover DSA Syllabus for placement.

Important points to remember about Data Structure and Algorithms comprises –

  1. Data Structures and Algorithms help solve problems efficiently by optimizing time and space complexity.
  2. They are a key focus in coding interviews, especially for top tech and Fortune 500 companies.

What are Data Structures ?

Data Structures are special ways of organizing and storing data in a computer so that we can use it easily and efficiently.

  • Think of them like containers or shelves where you keep your things in a neat order – like a list, a stack of plates, or a queue at a ticket counter.
  • Different types of data structures help solve different kinds of problems better.

What are Algorithms ?

Algorithms are step-by-step instructions or a set of rules to solve a problem or complete a task.

  • It’s like a cooking recipe that tells you exactly what to do, one step after another, to make a dish.
  • In computer science, algorithms help computers perform tasks like searching, sorting, or finding the best solution to a problem.

Here are some common examples of algorithms in Data Structures and Algorithms (DSA):

  1. Sorting Algorithms – Bubble Sort, Merge Sort, Quick Sort, Insertion Sort
  2. Searching Algorithms – Binary Search, Linear Search
  3. Graph Algorithms – Dijkstra’s Algorithm, BFS (Breadth-First Search), DFS (Depth-First Search), Kruskal’s and Prim’s Algorithm
  4. Dynamic Programming – Fibonacci Sequence, Knapsack Problem, Longest Common Subsequence
  5. Greedy Algorithms – Activity Selection, Huffman Coding, Fractional Knapsack

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What are Data Structures ?

Data Structures are special ways of organizing and storing data in a computer so that we can use it easily and efficiently.

  • Think of them like containers or shelves where you keep your things in a neat order – like a list, a stack of plates, or a queue at a ticket counter.
  • Different types of data structures help solve different kinds of problems better.

What are Algorithms ?

Algorithms are step-by-step instructions or a set of rules to solve a problem or complete a task.

  • It’s like a cooking recipe that tells you exactly what to do, one step after another, to make a dish.
  • In computer science, algorithms help computers perform tasks like searching, sorting, or finding the best solution to a problem.

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Searching

Searching algorithms are easy to learn but are really important for college semester exams and companies offering package between 3 – 6 LPA would ask direct searching questions in online test/ interviews.

Sorting

Sorting algorithms are easy to learn but are really important for college semester exams and companies offering package between 3 – 6 LPA would ask direct searching questions in online test/ interviews.

Data Structures and Algorithm Learn Sorting

Sorting

Sorting algorithms are easy to learn but are really important for college semester exams and companies offering package between 3 – 6 LPA would ask direct searching questions in online test/ interviews.

Data Structures and Algorithm Learn Sorting
Operating System Process Synchornization

Linked Lists

Linked List is one of the most crucial topics which is easy once understood thoroughly. This topic is very important for both your college semester examinations as well as for placement purposes.

Singly Linked List

  • Introduction to Linked List in Data Structure
  • Linked List in – C | C++ | Java
  • Singly Linked List in – C | C++ | Java
  • Insertion in singly Linked List – C | C++ | Java
    • Insertion at beginning in singly Linked List  – C | C++Java
    • Insertion at nth position in singly Linked List  – C | C++Java
    • Insertion at end in singly Linked List  – C | C++Java
  • Deletion in singly Linked List  – C | C++Java
    • Deletion from beginning in singly linked list : C | C++ | Java
    • Deletion from nth position in singly linked list : C | C++ | Java
    • Deletion from end in singly linked list : C | C++ | Java
  • Reverse a linked list without changing links between nodes (Data reverse only) – C | C++Java
  • Linked List Insertion and Deletion – C | C++Java
  • Reverse a linked list by changing links between nodes – C | C++Java
  • Linked List insertion in the middle – C | C++Java
  • Print reverse of a linked list without actually reversing – C |C++ | Java
  • Search an element in a linked list – C | C++Java
  • Insertion in a Sorted Linked List – C | C++Java
  • Delete alternate nodes of a Linked List – C | C++Java
  • Find middle of the linked list – C | C++Java
  • Reverse a linked list in groups of given size – C | C++Java
  • Find kth node from end of the linked list – C | C++Java
  • Append the last n nodes of a linked list to the beginning of the list – C | C++Java
  • Check whether linked list is palindrome or not – C | C++Java
  • Fold a Linked List – C | C++Java
  • Insert at a given position – C | C++Java
  • Delete at a given position – C | C++Java

Doubly Linked List

Circular Linked List

Linked Lists

Linked List is one of the most crucial topics which is easy once understood thoroughly. This topic is very important for both your college semester examinations as well as for placement purposes.

Singly Linked List

  • Introduction to Linked List in Data Structure
  • Linked List in –
    C
    C++
    Java
  • Singly Linked List in –
    C
    C++
    Java
  • Insertion in singly Linked List –
    C
    C++
    Java
    • Insertion at beginning in singly Linked List  –
      C
      C++
      Java
    • Insertion at nth position in singly Linked List  –
      C
      C++
      Java
    • Insertion at end in singly Linked List  –
      C
      C++
      Java
  • Deletion in singly Linked List  –
    C
    C++
    Java
    • Deletion from beginning in singly linked list :
      C
      C++
      Java
    • Deletion from nth position in singly linked list :
      C
      C++
      Java
    • Deletion from end in singly linked list :
      C
      C++
      Java
  • Reverse a linked list without changing links between nodes (Data reverse only) –
    C
    C++
    Java
  • Linked List Insertion and Deletion –
    C
    C++
    Java
  • Reverse a linked list by changing links between nodes –
    C
    C++
    Java
  • Linked List insertion in the middle –
    C
    C++
    Java
  • Print reverse of a linked list without actually reversing –
    C
    C++
    Java
  • Search an element in a linked list –
    C
    C++
    Java
  • Insertion in a Sorted Linked List –
    C
    C++
    Java
  • Delete alternate nodes of a Linked List –
    C
    C++
    Java
  • Find middle of the linked list –
    C
    C++
    Java
  • Reverse a linked list in groups of given size –
    C
    C++
    Java
  • Find kth node from end of the linked list –
    C
    C++
    Java
  • Append the last n nodes of a linked list to the beginning of the list –
    C
    C++
    Java
  • Check whether linked list is palindrome or not –
    C
    C++
    Java
  • Fold a Linked List –
    C
    C++
    Java
  • Insert at a given position –
    C
    C++
    Java
  • Delete at a given position –
    C
    C++
    Java

Doubly Linked List

Circular Linked List

Stacks and Queues

Stack is a topic that consists of easy to grasp concepts which help you score better in the college semester examinations as well as online tests/ interviews conducted by various companies. 

Stacks

Queues

Circular Queues

Priority Queue

  • Application of Priority Queue
  • Priority Queue Example
  • Priority Queue Introduction – C | C++ | Java
  • Priority Queue Implementation using Array – C | C++ | Java
  • Priority Queue using Linked List – C | C++ | Java
  • Priority Queue Insertion and Deletion- C | C++ | Java
Data structures and Algorithms: Stack

Stacks and Queues

Stack is a topic that consists of easy to grasp concepts which help you score better in the college semester examinations as well as online tests/ interviews conducted by various companies. 

Stacks

Queues

Circular Queues

Priority Queue

  • Application of Priority Queue
  • Priority Queue Example
  • Priority Queue Introduction –
    C
    C++
    Java
  • Priority Queue Implementation using Array –
    C
    C++
    Java
  • Priority Queue using Linked List –
    C
    C++
    Java
  • Priority Queue Insertion and Deletion-
    C
    C++
    Java
Data structures and Algorithms: Stack
Data structure and Algorithms: Trees

Trees

Trees are one of the most crucial topics in Data Structure which are a little complicated than the other topics in C. Questions from this topic are often asked in college semester examinations as well as Company interviews and online tests which are of a good difficulty level and have more weight age than other questions.

Introduction to Trees

Binary Trees

Binary Search Trees

Traversals

  • Traversal in Trees
  • Tree Traversals: Breadth-First Search (BFS) : C | C++ | Java
  • Tree Traversals: Depth First Search (DFS) : C | C++ | Java
  • Construct a Binary Tree from Postorder and Inorder

B – Trees

AVL Trees

  • AVL Trees

Complete Programs for Trees

  • Depth First Traversals – C | C++ | Java
  • Level Order Traversal – C | C++Java
  • Construct Tree from given Inorder and Preorder traversals – C | C++Java
  • Construct Tree from given Postorder and Inorder traversals – C | C++Java
  • Construct Tree from given Postorder and Preorder traversal – C | C++Java
  • Find size of the Binary tree – C | C++Java
  • Find the height of binary tree – C | C++Java
  • Find maximum in binary tree – C | C++Java
  • Check whether two tree are identical- CC++Java
  • Spiral Order traversal of Tree- CC++Java
  • Level Order Traversal LIne by Line – C | C++Java
  • Hand shaking lemma and some Impotant Tree Properties.
  • Check If binary tree if Foldable or not.- CC++Java
  • check whether tree is Symmetric  C| C++Java.
  • Check for Children-Sum in Binary Tree- C|C++Java
  • Sum of all nodes in Binary Tree- CC++ | Java
  • Lowest Common Ancestor in Binary Tree. CC++ | Java

Trees

Trees are one of the most crucial topics in Data Structure which are a little complicated than the other topics in C. Questions from this topic are often asked in college semester examinations as well as Company interviews and online tests which are of a good difficulty level and have more weight age than other questions.

Introduction to Trees

Binary Trees

Binary Search Trees

Traversals

  • Traversal in Trees
  • Tree Traversals: Breadth-First Search (BFS) :
    C
    C++
    Java
  • Tree Traversals: Depth First Search (DFS) :
    C
    C++
    Java
  • Construct a Binary Tree from Postorder and Inorder

B – Trees

AVL Trees

Complete Programs for Trees

Arrays

Arrays are one of the most frequently asked topics in both the college semester examinations and companies offering packages between 3.5 – 6 LPA often ask direct questions from this topic in the various online test/ interviews.

  • Introduction to Arrays – CC++ | Java
  • Introduction to 2-D Arrays – CC++ Java
  • Sorting of Array – C | C++ | Java
  • Array Rotation – CC++ | Java
  • Reverse an array or string- CC++ | Java
  • Find pairs in array with given sum – CC++ | Java
  • Sort the array in Waveform – CC++ | Java
  • Majority Element in Array – CC++ | Java
  • Boyer-Moore’s Voting Algorithm – CC++ | Java
  • K-pairs with smallest sum in 2 arrays – CC++ | Java
  • Largest Sum Contigous SubArray – CC++ | Java
  • Maximum Average Sub-array of K length – CC++ | Java
  • Size of sub-array with max sum – CC++ | Java
  • Sub-array with given sum – CC++ | Java
  • Triplet that sum to a given value – CC++ | Java
  • Segregate 0’s and 1’s in array – CC++ | Java
  • Segregate 0’s 1’s and 2’s in array – CC++ | Java
  • Sort elements in array by frequency – C | C++ | Java
  • Finding pythagorean triplets in an array – CC++ | Java
  • Reorder array using given indexes – CC++ | Java
  • Merging two sorted arrays – CC++ | Java
  • Minimum number of Merge Operations to make an Array Palindrome – CC++ | Java
  • Find Zeros to be Flipped so that number of Consecutive 1’s is maximized – CC++ | Java
Data Structures and algorithms: Array

Arrays

Arrays are one of the most frequently asked topics in both the college semester examinations and companies offering packages between 3.5 – 6 LPA often ask direct questions from this topic in the various online test/ interviews.

  • Introduction to Arrays –
    C
    C++
    Java
  • Introduction to 2-D Arrays –
    C
    C++ 
    Java
  • Sorting of Array –
    C
    C++
    Java
  • Array Rotation –
    C
    C++
    Java
  • Reverse an array or string-
    C
    C++
    Java
  • Find pairs in array with given sum –
    C
    C++
    Java
  • Sort the array in Waveform –
    C
    C++
    Java
  • Majority Element in Array –
    C
    C++
    Java
  • Boyer-Moore’s Voting Algorithm –
    C
    C++
    Java
  • K-pairs with smallest sum in 2 arrays –
    C
    C++
    Java
  • Largest Sum Contiguous Sub Array –
    C
    C++
    Java
  • Maximum Average Sub-array of K length –
    C
    C++
    Java
  • Size of sub-array with max sum –
    C
    C++
    Java
  • Sub-array with given sum –
    C
    C++
    Java
  • Triplet that sum to a given value –
    C
    C++
    Java
  • Segregate 0’s and 1’s in array –
    C
    C++
    Java
  • Segregate 0’s 1’s and 2’s in array –
    C
    C++
    Java
  • Sort elements in array by frequency –
    C
    C++
    Java
  • Finding Pythagorean triplets in an array –
    C
    C++
    Java
  • Reorder array using given indexes –
    C

    C++
    Java
  • Merging two sorted arrays –
    C

    C++
    Java
  • Minimum number of Merge Operations to make an Array Palindrome –
    C
    C++
    Java
  • Find Zeros to be Flipped so that number of Consecutive 1’s is maximized –
    C
    C++
    Java
Data Structures and algorithms: Array

Tower of Hanoi

Stack is a topic that consists of easy to grasp concepts which help you score better in the college semester examinations as well as online tests/ interviews conducted by various companies. 

DSA Assignments

DSA Assignments

Introduction to Data Structures

Lecture

Assignments

Arrays

Lecture

Assignments

Queues

Lecture

Assignments

Searching Algorithms

Lecture

Assignments

Sorting Algorithms

Lecture

Assignments

Hashing and Hash Table

Lecture

Assignments

Backtracking

Lecture

Assignments

Mapping

Lecture

Assignments

Recursion and Heap

Lecture

Assignments

Divide and Conquer

Lecture

Assignments

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