Arrays

100 Java Array Programming Questions

100 Java Array Programming Questions

A curated list of 100 array-focused programming questions in Java — arranged Basic → Medium → Difficult. Paste this into your Blogger post and edit the colors/font variables in the <style> block.

Java • Arrays • Practice
A. Basic Array Programs (1–40)
  1. Write a program to read and print elements of an array.
  2. Write a program to find the length of an array.
  3. Write a program to print array elements in reverse order.
  4. Write a program to find the sum of array elements.
  5. Write a program to find the average of array elements.
  6. Write a program to find the maximum element in an array.
  7. Write a program to find the minimum element in an array.
  8. Write a program to search for an element in an array (linear search).
  9. Write a program to count even numbers in an array.
  10. Write a program to count odd numbers in an array.
  11. Write a program to count positive numbers in an array.
  12. Write a program to count negative numbers in an array.
  13. Write a program to count zeros in an array.
  14. Write a program to find the sum of even elements in an array.
  15. Write a program to find the sum of odd elements in an array.
  16. Write a program to find the second largest element in an array.
  17. Write a program to find the second smallest element in an array.
  18. Write a program to find both the largest and smallest element in an array.
  19. Write a program to copy all elements of one array to another array.
  20. Write a program to merge two arrays into a third array.
  21. Write a program to reverse an array without using a second array.
  22. Write a program to sort an array in ascending order.
  23. Write a program to sort an array in descending order.
  24. Write a program to check if an array is sorted in ascending order.
  25. Write a program to remove duplicate elements from an array.
  26. Write a program to find the frequency of each element in an array.
  27. Write a program to print unique elements in an array.
  28. Write a program to print duplicate elements in an array.
  29. Write a program to rotate an array left by one position.
  30. Write a program to rotate an array right by one position.
  31. Write a program to rotate an array left by k positions.
  32. Write a program to rotate an array right by k positions.
  33. Write a program to swap the first and last element of an array.
  34. Write a program to insert an element at a specific position in an array.
  35. Write a program to delete an element from a specific position in an array.
  36. Write a program to find the index of an element in an array.
  37. Write a program to print the first repeating element in an array.
  38. Write a program to print the first non-repeating element in an array.
  39. Write a program to count occurrences of a given element in an array.
  40. Write a program to print all pairs of elements in an array.
B. Medium Array Programs (41–75)
  1. Write a program to reverse each half of an array separately.
  2. Write a program to find the missing number in a sequence array.
  3. Write a program to find the duplicate number in an array of n+1 integers.
  4. Write a program to segregate even and odd numbers in an array.
  5. Write a program to segregate 0s and 1s in an array.
  6. Write a program to segregate 0s, 1s, and 2s in an array (Dutch national flag).
  7. Write a program to move all zeros to the end of an array.
  8. Write a program to move all negative numbers to one side of an array.
  9. Write a program to find the intersection of two arrays.
  10. Write a program to find the union of two arrays.
  11. Write a program to find common elements between two arrays.
  12. Write a program to find the difference between two arrays.
  13. Write a program to check if two arrays are equal.
  14. Write a program to check if two arrays are disjoint.
  15. Write a program to check if an array is a subset of another array.
  16. Write a program to find the maximum product of two elements in an array.
  17. Write a program to find the maximum sum subarray (Kadane’s algorithm).
  18. Write a program to find the minimum sum subarray.
  19. Write a program to find the longest increasing subsequence in an array.
  20. Write a program to find the longest decreasing subsequence in an array.
  21. Write a program to find the longest consecutive sequence in an array.
  22. Write a program to check if an array contains duplicate elements within k distance.
  23. Write a program to print leaders in an array (element greater than all elements to its right).
  24. Write a program to find equilibrium index (where left sum = right sum).
  25. Write a program to find peak elements in an array.
  26. Write a program to find the maximum difference between two elements in an array.
  27. Write a program to find the minimum difference between two elements in an array.
  28. Write a program to calculate the prefix sum of an array.
  29. Write a program to calculate the suffix sum of an array.
  30. Write a program to find a pair of elements whose sum is equal to a given number.
  31. Write a program to find all triplets whose sum is equal to a given number.
  32. Write a program to find all quadruplets whose sum is equal to a given number.
  33. Write a program to find the majority element in an array.
  34. Write a program to rearrange an array so that positive and negative numbers alternate.
  35. Write a program to rearrange an array such that arr[i] = i (if possible).
C. Difficult Array Programs (76–100)
  1. Write a program to find the maximum product subarray.
  2. Write a program to find the subarray with given sum (sliding window).
  3. Write a program to find the smallest subarray with sum greater than a given value.
  4. Write a program to find the largest subarray with equal number of 0s and 1s.
  5. Write a program to find the maximum circular subarray sum.
  6. Write a program to find the maximum sum of non-adjacent elements.
  7. Write a program to find the median of two sorted arrays.
  8. Write a program to find the kth smallest element in an array.
  9. Write a program to find the kth largest element in an array.
  10. Write a program to find the kth missing number in a sorted array.
  11. Write a program to merge overlapping intervals in an array.
  12. Write a program to find the minimum number of jumps to reach the end of an array.
  13. Write a program to find the minimum number of platforms required (train problem with arrays).
  14. Write a program to maximize stock profit from given price array (buy/sell once).
  15. Write a program to maximize stock profit (buy/sell multiple times).
  16. Write a program to maximize stock profit (at most two transactions).
  17. Write a program to check if an array can be divided into two parts with equal sum.
  18. Write a program to check if an array can be partitioned into k subsets with equal sum.
  19. Write a program to find the maximum length subarray with a given XOR.
  20. Write a program to find the maximum XOR of two elements in an array.
  21. Write a program to count inversions in an array (using merge sort).
  22. Write a program to find the minimum swaps required to sort an array.
  23. Write a program to find the next lexicographic permutation of an array.
  24. Write a program to solve the trapping rainwater problem.
  25. Write a program to solve the maximum histogram area problem using arrays.

Tip: To change colors or font, edit the CSS variables at the top of this document (inside the <style> block). Copy the entire HTML and paste into your Blogger post in HTML mode.


    

  


































Comments











Post a Comment
























Popular posts from this blog



























Image







            Problem of the Day:                             Remove Duplicate Characters and Digits with Different Rules   You are given a string s consisting of lowercase English letters and digits (0–9).          You must transform the string in two steps:   Characters (a–z):   Traverse from left to right.   Keep only the first occurrence of each character.   Remove all later duplicates.    Digits (0–9):  Traverse from right to left.   Keep only the first digit you encounter (the rightmost occurrence in the original string).   Remove earlier duplicates.       Return the final transformed string.                1.Input: programming123321     After Step1: progamin123321     Final: progamin321    (keeps the rightmost 1,2,3 — final digits appear as the left-to-right order of their last occurrences)      2. Input: abc11223344     After Step1: abc11223344       Final: abc1234     3. Input: a1b2c1d2e3     After Step1: a1b2c1d2e3      Final: abc1d2e3            








Read more










Strings





















            100 Java String Programming Questions                              100 Java String Programming Questions          A clean list of 100 string-focused programming questions in Java — arranged Basic → Intermediate → Advanced. Copy this HTML into your Blogger post's HTML editor and tweak the CSS variables at the top to change colors and fonts.                    A. Basic String Programs (1–40)                 Write a program to find the length of a string.                   Write a program to print each character of a string.                                     Write a program to reverse a string.          Write a program to check if a string is a palindrome.          Write a program to count vowels in a string.          Write a program to count consonants in a string.          Write a program to count digits in a string.          Write a program to count spaces in a string.          Write a program to count special characters in a string.          Write a program to conver...








Read more