Practice 50 PHP Searching and Sorting Programming Questions

Practice 50 PHP Searching and Sorting Programming Questions

Q1. Write a PHP program to implement linear search on an array of integers.
Input: Array = [10, 20, 30, 40, 50], Search Key = 30  
Expected Output: "Element found at index 2"

Q2. Write a PHP program to implement binary search on a sorted array of integers.  
Input: Array = [1, 2, 3, 4, 5], Search Key = 4  
Expected Output: "Element found at index 3"

Q3. Write a PHP program to sort an array of integers using the Bubble Sort algorithm.  
Input: Array = [64, 34, 25, 12, 22, 11, 90]  
Expected Output: Sorted Array = [11, 12, 22, 25, 34, 64, 90]

Q4. Write a PHP program to sort an array of integers using the Selection Sort algorithm.  
Input: Array = [29, 10, 14, 37, 13]  
Expected Output: Sorted Array = [10, 13, 14, 29, 37]

Q5. Write a PHP program to sort an array of integers using the Insertion Sort algorithm.  
Input: Array = [9, 5, 1, 4, 3]  
Expected Output: Sorted Array = [1, 3, 4, 5, 9]

Q6. Write a PHP program to find the maximum element in an array.  
Input: Array = [3, 29, 12, 44, 5]  
Expected Output: "Maximum element is 44"

Q7. Write a PHP program to find the minimum element in an array.  
Input: Array = [3, 29, 12, 44, 5]  
Expected Output: "Minimum element is 3"

Q8. Write a PHP program to implement recursive binary search on a sorted array.  
Input: Array = [2, 4, 6, 8, 10], Search Key = 6  
Expected Output: "Element found at index 2"

Q9. Write a PHP program to sort an array of integers using the Merge Sort algorithm.  
Input: Array = [12, 11, 13, 5, 6, 7]  
Expected Output: Sorted Array = [5, 6, 7, 11, 12, 13]

Q10. Write a PHP program to sort an array of integers using the Quick Sort algorithm.  
Input: Array = [10, 80, 30, 90, 40, 50, 70]  
Expected Output: Sorted Array = [10, 30, 40, 50, 70, 80, 90]

Q11. Write a PHP program to implement linear search to find all occurrences of a number in an array.  
Input: Array = [10, 20, 10, 30, 10], Search Key = 10  
Expected Output: "Element found at indices: 0, 2, 4"

Q12. Write a PHP program to check if an array is already sorted in ascending order.  
Input: Array = [1, 2, 3, 4, 5]  
Expected Output: "Array is sorted in ascending order"

Q13. Write a PHP program to implement the counting sort algorithm for integers.  
Input: Array = [4, 2, 2, 8, 3, 3, 1]  
Expected Output: Sorted Array = [1, 2, 2, 3, 3, 4, 8]

Q14. Write a PHP program to sort an array of strings using Bubble Sort.  
Input: Array = ["banana", "apple", "cherry", "date"]  
Expected Output: Sorted Array = ["apple", "banana", "cherry", "date"]

Q15. Write a PHP program to find the second smallest element in an array.  
Input: Array = [7, 1, 3, 9, 5]  
Expected Output: "Second smallest element is 3"

Q16. Write a PHP program to find the second largest element in an array.  
Input: Array = [7, 1, 3, 9, 5]  
Expected Output: "Second largest element is 7"

Q17. Write a PHP program to implement a search for a string in an array of strings.  
Input: Array = ["apple", "banana", "cherry"], Search Key = "banana"  
Expected Output: "String found at index 1"

Q18. Write a PHP program to count the number of times a specific number appears in an array.  
Input: Array = [1, 2, 2, 3, 4, 2], Search Key = 2  
Expected Output: "The number 2 appears 3 times"

Q19. Write a PHP program to sort an array of integers using the Heap Sort algorithm.  
Input: Array = [4, 10, 3, 5, 1]  
Expected Output: Sorted Array = [1, 3, 4, 5, 10]

Q20. Write a PHP program to sort an array of integers using the Shell Sort algorithm.  
Input: Array = [12, 34, 54, 2, 3]  
Expected Output: Sorted Array = [2, 3, 12, 34, 54]

Q21. Write a PHP program to find the median of an unsorted array.  
Input: Array = [12, 4, 5, 3, 8, 7]  
Expected Output: "Median is 6"

Q22. Write a PHP program to sort an array of integers using descending order Bubble Sort.  
Input: Array = [1, 4, 2, 8, 5]  
Expected Output: Sorted Array = [8, 5, 4, 2, 1]

Q23. Write a PHP program to search for an element in a 2D array.  
Input: Array = [[1, 2], [3, 4]], Search Key = 3  
Expected Output: "Element found at row 1, column 0"

Q24. Write a PHP program to implement jump search on a sorted array of integers.  
Input: Array = [1, 3, 5, 7, 9], Search Key = 7  
Expected Output: "Element found at index 3"

Q25. Write a PHP program to implement the comb sort algorithm.  
Input: Array = [8, 4, 1, 56, 3, -44, 23, -6, 28, 0]  
Expected Output: Sorted Array = [-44, -6, 0, 1, 3, 4, 8, 23, 28, 56]

Q26. Write a PHP program to find the kth smallest element in an array.  
Input: Array = [7, 10, 4, 3, 20, 15], k = 3  
Expected Output: "3rd smallest element is 7"

Q27. Write a PHP program to find the kth largest element in an array.  
Input: Array = [7, 10, 4, 3, 20, 15], k = 2  
Expected Output: "2nd largest element is 15"

Q28. Write a PHP program to find the position of the first negative number in an array.  
Input: Array = [5, -3, 10, -8, 12]  
Expected Output: "First negative number is at index 1"

Q29. Write a PHP program to sort an array of strings in reverse alphabetical order.  
Input: Array = ["apple", "banana", "cherry"]  
Expected Output: Sorted Array = ["cherry", "banana", "apple"]

Q30. Write a PHP program to search for multiple values in an array and return their indices.  
Input: Array = [1, 5, 7, 5, 3, 7], Search Keys = [5, 7]  
Expected Output: "5 found at indices: 1, 3; 7 found at indices: 2, 5"

Q31. Write a PHP program to sort an array of integers using Gnome Sort.  
Input: Array = [34, 2, 10, -9]  
Expected Output: Sorted Array = [-9, 2, 10, 34]

Q32. Write a PHP program to implement a case-insensitive search for a string in an array.  
Input: Array = ["Apple", "Banana", "Cherry"], Search Key = "banana"  
Expected Output: "String found at index 1"

Q33. Write a PHP program to implement ternary search on a sorted array.  
Input: Array = [1, 3, 5, 7, 9, 11, 13], Search Key = 11  
Expected Output: "Element found at index 5"

Q34. Write a PHP program to remove duplicate values from a sorted array.  
Input: Array = [1, 1, 2, 3, 3, 4, 4, 5]  
Expected Output: Array without duplicates = [1, 2, 3, 4, 5]

Q35. Write a PHP program to count the number of elements less than a given value in a sorted array.  
Input: Array = [10, 20, 30, 40, 50], Search Value = 35  
Expected Output: "3 elements are less than 35"

Q36. Write a PHP program to check if two arrays are equal after sorting.  
Input: Array1 = [3, 1, 2], Array2 = [2, 3, 1]  
Expected Output: "Arrays are equal"

Q37. Write a PHP program to find the largest even number in an array.  
Input: Array = [5, 12, 3, 18, 7]  
Expected Output: "Largest even number is 18"

Q38. Write a PHP program to find the largest odd number in an array.  
Input: Array = [4, 8, 11, 15, 2]  
Expected Output: "Largest odd number is 15"

Q39. Write a PHP program to count the number of even numbers in an array.  
Input: Array = [5, 12, 3, 18, 7]  
Expected Output: "2 even numbers found"

Q40. Write a PHP program to count the number of odd numbers in an array.  
Input: Array = [4, 8, 11, 15, 2]  
Expected Output: "2 odd numbers found"

Q41. Write a PHP program to implement exponential search for a number in a sorted array.  
Input: Array = [1, 2, 3, 4, 5, 6, 7, 8], Search Key = 6  
Expected Output: "Element found at index 5"

Q42. Write a PHP program to reverse an array without using PHP's built-in functions.  
Input: Array = [1, 2, 3, 4, 5]  
Expected Output: Reversed Array = [5, 4, 3, 2, 1]

Q43. Write a PHP program to find the smallest positive number missing from an unsorted array.  
Input: Array = [3, 4, -1, 1]  
Expected Output: "Smallest positive missing number is 2"

Q44. Write a PHP program to sort an array of numbers such that all negative numbers appear before positive numbers.  
Input: Array = [-12, 11, -13, -5, 6, -7, 5, -3, -6]  
Expected Output: [-12, -13, -5, -7, -3, -6, 11, 6, 5]

Q45. Write a PHP program to check if a number exists in a multidimensional array.  
Input: Array = [[1, 2, 3], [4, 5, 6], [7, 8, 9]], Search Key = 5  
Expected Output: "Element found"

Q46. Write a PHP program to count the number of elements greater than a given value in an array.  
Input: Array = [10, 20, 30, 40, 50], Search Value = 25  
Expected Output: "3 elements are greater than 25"

Q47. Write a PHP program to find the intersection of two sorted arrays.  
Input: Array1 = [1, 3, 4, 5], Array2 = [3, 4, 6, 7]  
Expected Output: Intersection = [3, 4]

Q48. Write a PHP program to find the union of two sorted arrays without duplicates.  
Input: Array1 = [1, 2, 3], Array2 = [2, 3, 4]  
Expected Output: Union = [1, 2, 3, 4]

Q49. Write a PHP program to merge two sorted arrays into one sorted array.  
Input: Array1 = [1, 3, 5], Array2 = [2, 4, 6]  
Expected Output: Merged Array = [1, 2, 3, 4, 5, 6]

Q50. Write a PHP program to implement a rotated binary search to find a number in a rotated sorted array.  
Input: Array = [4, 5, 6, 7, 0, 1, 2], Search Key = 1  
Expected Output: "Element found at index 5"