Practice 100 C# Basic Algorithm Programming Questions, TechnoVlogs

Practice 100 C# Basic Algorithm Programming Questions


Q1. Write a C# program to find the largest of three numbers.  
  Input: a = 10, b = 20, c = 15  
  Output: 20

Q2. Write a C# program to calculate the factorial of a number using recursion.  
  Input: n = 5  
  Output: 120

Q3. Write a C# program to calculate the Fibonacci sequence up to n terms.  
  Input: n = 5  
  Output: 0, 1, 1, 2, 3

Q4. Write a C# program to check if a number is a palindrome.  
  Input: 121  
  Output: Palindrome

Q5. Write a C# program to implement binary search on a sorted array.  
  Input: Array = [1, 3, 5, 7, 9], Target = 5  
  Output: Index: 2

Q6. Write a C# program to find the greatest common divisor (GCD) of two numbers.  
  Input: a = 56, b = 98  
  Output: 14

Q7. Write a C# program to find the least common multiple (LCM) of two numbers.  
  Input: a = 4, b = 6  
  Output: 12

Q8. Write a C# program to reverse the digits of a number.  
  Input: 1234  
  Output: 4321

Q9. Write a C# program to find the sum of n natural numbers.  
  Input: n = 10  
  Output: 55

Q10. Write a C# program to find the product of n natural numbers.  
   Input: n = 5  
   Output: 120

Q11. Write a C# program to calculate the power of a number (x^y) without using Math.Pow().  
   Input: x = 2, y = 3  
   Output: 8

Q12. Write a C# program to print all prime factors of a number.  
   Input: n = 28  
   Output: 2, 7

Q13. Write a C# program to check if a number is a perfect square.  
   Input: n = 16  
   Output: True

Q14. Write a C# program to generate all subsets of a set.  
   Input: Set = [1, 2, 3]  
   Output:  
   [], [1], [2], [3], [1, 2], [1, 3], [2, 3], [1, 2, 3]

Q15. Write a C# program to count the number of inversions in an array.  
   Input: [2, 4, 1, 3, 5]  
   Output: 3

Q16. Write a C# program to implement the Sieve of Eratosthenes to find all prime numbers up to n.  
   Input: n = 10  
   Output: 2, 3, 5, 7

Q17. Write a C# program to find the longest common prefix of an array of strings.  
   Input: ["flower", "flow", "flight"]  
   Output: "fl"

Q18. Write a C# program to perform insertion sort on an array.  
   Input: [3, 1, 4, 2]  
   Output: [1, 2, 3, 4]

Q19. Write a C# program to perform selection sort on an array.  
   Input: [3, 1, 4, 2]  
   Output: [1, 2, 3, 4]

Q20. Write a C# program to perform bubble sort on an array.  
   Input: [3, 1, 4, 2]  
   Output: [1, 2, 3, 4]

Q21. Write a C# program to perform merge sort on an array.  
   Input: [38, 27, 43, 3, 9, 82, 10]  
   Output: [3, 9, 10, 27, 38, 43, 82]

Q22. Write a C# program to perform quicksort on an array.  
   Input: [10, 7, 8, 9, 1, 5]  
   Output: [1, 5, 7, 8, 9, 10]

Q23. Write a C# program to find the minimum and maximum element in an array.  
   Input: [3, 5, 1, 9, 2]  
   Output: Min: 1, Max: 9

Q24. Write a C# program to find the missing number in an array of 1 to n.  
   Input: [1, 2, 4, 5]  
   Output: 3

Q25. Write a C# program to find the first non-repeating character in a string.  
   Input: swiss  
   Output: w

Q26. Write a C# program to remove all duplicates from a sorted array.  
   Input: [1, 1, 2, 2, 3, 4, 4]  
   Output: [1, 2, 3, 4]

Q27. Write a C# program to find the kth smallest element in an array.  
   Input: Array = [7, 10, 4, 3, 20, 15], k = 3  
   Output: 7

Q28. Write a C# program to sort an array of 0s, 1s, and 2s.  
   Input: [2, 0, 2, 1, 1, 0]  
   Output: [0, 0, 1, 1, 2, 2]

Q29. Write a C# program to find the maximum sum subarray using Kadane’s Algorithm.  
   Input: [-2, 1, -3, 4, -1, 2, 1, -5, 4]  
   Output: 6

Q30. Write a C# program to check if a string is a valid palindrome, ignoring non-alphanumeric characters.  
   Input: "A man, a plan, a canal: Panama"  
   Output: True

Q31. Write a C# program to merge two sorted arrays into a single sorted array.  
   Input: Array1 = [1, 3, 5], Array2 = [2, 4, 6]  
   Output: [1, 2, 3, 4, 5, 6]

Q32. Write a C# program to calculate the nth Fibonacci number using dynamic programming.  
   Input: n = 10  
   Output: 55

Q33. Write a C# program to count the number of bits set to 1 in the binary representation of a number.  
   Input: n = 9  
   Output: 2

Q34. Write a C# program to rotate an array to the left by k steps.  
   Input: Array = [1, 2, 3, 4, 5], k = 2  
   Output: [3, 4, 5, 1, 2]

Q35. Write a C# program to find the intersection of two arrays using a hash set.  
   Input: Array1 = [1, 2, 2, 1], Array2 = [2, 2]  
   Output: [2]

Q36. Write a C# program to implement the Two Sum algorithm.  
   Input: Array = [2, 7, 11, 15], Target = 9  
   Output: Indices: [0, 1]

Q37. Write a C# program to find the maximum product of two elements in an array.  
   Input: [1, 5, 4, 5]  
   Output: 16

Q38. Write a C# program to find the smallest number greater than n in an array.  
   Input: Array = [1, 3, 5, 7], n = 4  
   Output: 5

Q39. Write a C# program to check if two strings are permutations of each other.  
   Input: str1 = "abc", str2 = "bca"  
   Output: True

Q40. Write a C# program to find the equilibrium index of an array.  
   Input: [1, 3, 5, 2, 2]  
   Output: 2

Q41. Write a C# program to count the number of vowels and consonants in a string.  
   Input: "hello"  
   Output: Vowels: 2, Consonants: 3

Q42. Write a C# program to find the second largest element in an array.  
   Input: [10, 20, 4, 45, 99]  
   Output: 45

Q43. Write a C# program to remove duplicate elements from an unsorted array.  
   Input: [4, 5, 9, 4, 9, 7, 6]  
   Output: [4, 5, 9, 7, 6]

Q44. Write a C# program to count the number of occurrences of each element in an array.  
   Input: [2, 3, 2, 4, 2, 4, 3]  
   Output:  
   2: 3  
   3: 2  
   4: 2  

Q45. Write a C# program to find the longest palindrome substring in a string.  
   Input: "babad"  
   Output: "bab" or "aba"

Q46. Write a C# program to implement linear search in an array.  
   Input: Array = [1, 3, 5, 7, 9], Target = 7  
   Output: Index: 3

Q47. Write a C# program to calculate the sum of all even numbers and odd numbers separately in an array.  
   Input: [1, 2, 3, 4, 5, 6]  
   Output: Even Sum: 12, Odd Sum: 9

Q48. Write a C# program to check if a given string is an anagram of another string.  
   Input: str1 = "listen", str2 = "silent"  
   Output: True

Q49. Write a C# program to find the sum of all elements in a 2D array.  
   Input:  
   [[1, 2],  
    [3, 4]]  

   Output: 10

Q50. Write a C# program to implement a basic Caesar Cipher encryption.  
   Input: Text: "hello", Shift: 3  
   Output: "khoor"

Q51. Write a C# program to check if an array is sorted in ascending order.  
   Input: [1, 2, 3, 4, 5]  
   Output: True

Q52. Write a C# program to find the largest product of any three numbers in an array.  
   Input: [1, 10, -5, 1, -100]  
   Output: 5000

Q53. Write a C# program to calculate the sum of the boundary elements in a matrix.  
   Input:    
   [[1, 2, 3],  
    [4, 5, 6],  
    [7, 8, 9]]  
     
   Output: 40

Q54. Write a C# program to reverse a string without using inbuilt functions.  
   Input: "hello"  
   Output: "olleh"

Q55. Write a C# program to calculate the average of all numbers in an array.  
   Input: [1, 2, 3, 4, 5]  
   Output: 3

Q56. Write a C# program to find all pairs of numbers in an array that sum to a given value.  
   Input: Array = [1, 5, 7, -1], Sum = 6  
   Output: Pairs: (1, 5), (7, -1)

Q57. Write a C# program to remove all vowels from a string.  
   Input: "beautiful"  
   Output: "btfl"

Q58. Write a C# program to check if a given number is an Armstrong number.  
   Input: 153  
   Output: True

Q59. Write a C# program to find the length of the longest word in a sentence.  
   Input: "I love programming"  
   Output: 11

Q60. Write a C# program to calculate the Hamming distance between two strings.  
   Input: str1 = "karolin", str2 = "kathrin"  
   Output: 3

Q61. Write a C# program to check if a number is a happy number.  
   Input: 19  
   Output: True

Q62. Write a C# program to find the first repeated character in a string.  
   Input: "programming"  
   Output: r

Q63. Write a C# program to find the sum of the digits of a number until a single digit is obtained.  
   Input: 9875  
   Output: 2

Q64. Write a C# program to check if two strings are rotations of each other.  
   Input: str1 = "abcd", str2 = "cdab"  
   Output: True

Q65. Write a C# program to count the number of words in a sentence.  
   Input: "Hello, world!"  
   Output: 2

Q66. Write a C# program to reverse the words in a sentence.  
   Input: "I love C#"  
   Output: "C# love I"

Q67. Write a C# program to calculate the product of all elements in an array.  
   Input: [1, 2, 3, 4]  
   Output: 24

Q68. Write a C# program to implement the Tower of Hanoi algorithm for n disks.  
   Input: n = 3  
   Output:     
   Move disk 1 from A to C  
   Move disk 2 from A to B  
   Move disk 1 from C to B  
   Move disk 3 from A to C  
   Move disk 1 from B to A  
   Move disk 2 from B to C  
   Move disk 1 from A to C  
   
Q69. Write a C# program to generate Pascal's Triangle for n rows.  
   Input: n = 5  
   Output:  
   1  
   1 1  
   1 2 1  
   1 3 3 1  
   1 4 6 4 1  
   
Q70. Write a C# program to find the longest increasing subsequence in an array.  
   Input: [10, 22, 9, 33, 21, 50, 41, 60, 80]  
   Output: 6

Q71. Write a C# program to find the transpose of a matrix.  
   Input:  
   [[1, 2],  
    [3, 4]]  
     
   Output: 
   [[1, 3],  
    [2, 4]]  

Q72. Write a C# program to check if a matrix is symmetric.  
   Input:  
   [[1, 2, 3],  
    [2, 4, 5],  
    [3, 5, 6]]  
     
   Output: True

Q73. Write a C# program to find all prime numbers in an interval.  
   Input: Start = 10, End = 20  
   Output: 11, 13, 17, 19

Q74. Write a C# program to calculate the sum of diagonal elements of a square matrix.  
   Input:  
   [[1, 2, 3],  
    [4, 5, 6],  
    [7, 8, 9]]  
     
   Output: 15

Q75. Write a C# program to calculate the area of a triangle using Heron's formula.  
   Input: a = 3, b = 4, c = 5  
   Output: 6

Q76. Write a C# program to find the missing character in a string to make it a pangram.  
   Input: "The quick brown fox jumps over the lazy do"  
   Output: "g"

Q77. Write a C# program to find the longest common subsequence of two strings.  
   Input: str1 = "abcde", str2 = "ace"  
   Output: "ace"

Q78. Write a C# program to find the sum of all proper divisors of a number.  
   Input: 28  
   Output: 28

Q79. Write a C# program to calculate the digital root of a number.  
   Input: 12345  
   Output: 6

Q80. Write a C# program to count the number of trailing zeros in the factorial of a number.  
   Input: n = 10  
   Output: 2

Q81. Write a C# program to check if a string has balanced parentheses.  
   Input: "((a+b)*c)"  
   Output: True

Q82. Write a C# program to implement binary search in a sorted array.  
   Input: Array = [1, 3, 5, 7, 9], Target = 5  
   Output: Index: 2

Q83. Write a C# program to find the GCD (Greatest Common Divisor) of two numbers.  
   Input: a = 56, b = 98  
   Output: 14

Q84. Write a C# program to calculate the power of a number using recursion.  
   Input: Base = 2, Exponent = 5  
   Output: 32

Q85. Write a C# program to find the sum of the squares of the first n natural numbers.  
   Input: n = 5  
   Output: 55

Q86. Write a C# program to generate all permutations of a string.  
   Input: "abc"  
   Output: "abc, acb, bac, bca, cab, cba"

Q87. Write a C# program to implement the Sieve of Eratosthenes to find all prime numbers up to n.  
   Input: n = 30  
   Output: [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]

Q88. Write a C# program to find the maximum depth of nested parentheses in a string.  
   Input: "(a(b(c)d)e)"  
   Output: 3

Q89. Write a C# program to find the majority element in an array.  
   Input: [3, 3, 4, 2, 4, 4, 2, 4, 4]  
   Output: 4

Q90. Write a C# program to count the number of distinct elements in an array.  
   Input: [1, 2, 2, 3, 4, 4, 5]  
   Output: 5

Q91. Write a C# program to implement Bubble Sort.  
   Input: [64, 34, 25, 12, 22, 11, 90]  
   Output: [11, 12, 22, 25, 34, 64, 90]

Q92. Write a C# program to find the longest substring without repeating characters.  
   Input: "abcabcbb"  
   Output: "abc"

Q93. Write a C# program to check if a number is a power of two.  
   Input: n = 16  
   Output: True

Q94. Write a C# program to find the first k largest elements in an array.  
   Input: Array = [1, 23, 12, 9, 30, 2, 50], k = 3  
   Output: [50, 30, 23]

Q95. Write a C# program to calculate the nth Catalan number.  
   Input: n = 4  
   Output: 14

Q96. Write a C# program to implement insertion sort.  
   Input: [12, 11, 13, 5, 6]  
   Output: [5, 6, 11, 12, 13]

Q97. Write a C# program to calculate the sum of all prime numbers up to n.  
   Input: n = 10  
   Output: 17

Q98. Write a C# program to find the row with the maximum sum in a 2D array.  
   Input:  
   [[1, 2, 3],  
    [4, 5, 6],  
    [7, 8, 9]]  
     
   Output: Row 3, Sum: 24

Q99. Write a C# program to check if a given number is a perfect square.  
   Input: n = 49  
   Output: True

Q100. Write a C# program to reverse the order of columns in a 2D array.  
   Input:  
   [[1, 2, 3],  
    [4, 5, 6],  
    [7, 8, 9]]  
     
   Output:  
   [[3, 2, 1],  
    [6, 5, 4],  
    [9, 8, 7]]

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