Programming Problems

Welcome to my collection of programming problems and their solutions implemented in multiple languages: C, C++, Java, and Python.

Each problem is categorized (e.g., Basic, Intermediate, Advanced). Click on a problem to see the solutions in your preferred programming language.

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Table of Contents

• Basic Questions
• Intermediate Questions
• Advanced Questions
• Contributing
• License

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Basic Questions

1. Write a program to reverse a string

   

2. Find the largest and smallest number in an array

   

3. Check if a string is a palindrome

   

4. Write a program to check if a number is prime

   

5. Check if a number is a palindrome

   

6. Print the Fibonacci series up to n terms (iteration)

   

7. Find duplicates in an array

   

8. Check if a number is even or odd

   

9. Write a program to find the factorial of a number

   

10. Swap two numbers without using a third variable

    

11. Write a program to count the number of vowels and consonants in a string

    

12. Implement a basic calculator for addition, subtraction, multiplication, and division

    

13. Find the sum of the digits of a given number

    

14. Check if a number is prime or composite

    

15. Find the missing number in an array of size n containing numbers from 1 to n+1 in C

    

16. Find all pairs in an array whose sum is equal to a given number

    

17. Write a program to remove duplicates from a sorted array

    

18. Write a program to move all zeros in an array to the end

    

19. Implement a program to check if a string contains all unique characters

    

20. Reverse the words in a sentence without reversing the letters

    

21. Reverse a linked list (iterative)

    

22. Reverse a linked list (recursive)

    

23. Find the middle element of a linked list in one traversal

    

24. Implement a queue using a circular array

    

25. Solve the Activity Selection Problem

    

26. Write a program to find the largest number possible from an array of numbers

    

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Intermediate Questions

1. Implement a stack using an array

   

2. Implement a queue using an array

   

3. Merge two sorted arrays into a single sorted array

   

4. Solve the Fibonacci series using recursion

   

5. Implement bubble sort algorithm

   

6. Implement insertion sort algorithm

   

7. Implement binary search for a sorted array

   

8. Implement binary search for an unsorted array

   

9. Find the second largest number in an array

   

10. Write a program to check if two strings are anagrams

    

11. Convert a decimal number to binary

    

12. Find the GCD (Greatest Common Divisor) and LCM (Least Common Multiple) of two numbers

    

13. Write a program to rotate an array by k positions

    

14. Implement a stack and its operations (push, pop, peek) using an array

    

15. Find the majority element in an array (element that appears more than n2 times)

    

16. Find the longest common prefix in an array of strings

    

17. Find the first non-repeating character in a string

    

18. Write a program to implement string compression (e.g., aaabb → a3b2)

    

19. Merge two sorted linked lists

    

20. Implement a queue using an array

    

21. Detect and remove a cycle in a linked list

    

22. Write a program to evaluate a postfix expression

    

23. Implement a min stack that supports push, pop, and retrieving the minimum element in constant time

    

24. Solve the 01 Knapsack Problem

    

25. Find the length of the longest increasing subsequence

    

26. Solve the Coin Change Problem (minimum coins needed to make a sum)

    

27. Find the longest common subsequence of two strings

    

28. Implement Huffman Encoding

    

29. Find the minimum number of coins needed for a given amount using a greedy approach

    

30. Generate all subsets of a given set using recursion

    

31. Solve the Fractional Knapsack Problem

    

32. Solve the Topological Sorting Problem for a directed acyclic graph (DAG)

    

33. Write a program to detect a cycle in a directed graph using DFS

    

34. Tree traversals (inorder, preorder, postorder)

    

35. Write a program to find the intersection of two sorted arrays

    

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Advanced Questions

1. Implement merge sort algorithm

   

2. Implement quicksort algorithm

   

3. Write a program to check if a linked list is a palindrome

   

4. Implement a queue using two stacks

   

5. Solve the N-Queens Problem using backtracking

   

6. Write a program to detect a cycle in a linked list

   

7. Find the shortest path in a graph using Dijkstra’s Algorithm

   

8. Check if a binary tree is a valid binary search tree (BST)

   

9. Write a program to solve the Knapsack Problem using dynamic programming

   

10. Implement depth-first search (DFS) for a graph

    

11. Implement breadth-first search (BFS) for a graph

    

12. Find the maximum area of a rectangle in a histogram

    

13. Implement the Tower of Hanoi

    

14. Write a program to compute the nth Catalan number

    

15. Design a hash map from scratch using an array and linked list

    

16. Find the connected components of an undirected graph

    

17. Implement Floyd-Warshall Algorithm for all-pairs shortest paths

    

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Contributing

Contributions are welcome! If you have a new solution or an improvement:

1. Fork this repository.
2. Create a new branch for your feature/fix.
3. Commit your changes and open a pull request.

Please ensure your code follows the existing structure.

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License

Distributed under the MIT License. See LICENSE for more information.