Java Coding Practice

Solve Count Valid Array Partitions using Java Language

Solve Count Valid Array Partitions using Java to enhance your skills with java coding practice , master coding concepts, and prepare for interviews with practical exercises and detailed solutions.

Count Valid Array Partitions

Difficulty : Medium

Categories :

  • Recursion

Given an array of integers arr, your task is to find all possible ways to partition the array into groups such that:

  • Each group's sum must be divisible by its size
  • Each element must belong to exactly one group
  • Groups can be of any size ≥ 1

Return the number of valid partitionings.

Constraints:

  • 1 ≤ arr.length ≤ 15
  • -100 ≤ arr[i] ≤ 100
  • Must use recursion in the solution

Examples:

Input: arr = [1,2,3,4]
Output: 4
Explanation: Valid partitionings are:
[1,2,3,4] (sum=10, size=4, 10÷4=2.5 not valid)
[1,2,3] [4] (sum=6, size=3, 6÷3=2 valid | sum=4, size=1, 4÷1=4 valid)
[1,3] [2,4] (sum=4, size=2, 4÷2=2 valid | sum=6, size=2, 6÷2=3 valid)
[1] [2,3,4] (sum=1, size=1, 1÷1=1 valid | sum=9, size=3, 9÷3=3 valid)
Total valid partitionings = 3
Input: arr = [3,3,3]
Output: 2
Explanation: Valid partitionings are:
[3,3,3] (sum=9, size=3, 9÷3=3 valid)
[3] [3,3] (sum=3, size=1, 3÷1=3 valid | sum=6, size=2, 6÷2=3 valid)

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Choose from the following categories

Arrays A collection of elements stored in contiguous memory locations, allowing efficient random access and manipulation.

Linked Lists A linear data structure where each element (node) points to the next, offering dynamic memory allocation and efficient insertions/deletions.

Trees A hierarchical data structure with nodes connected by edges, used in applications like databases, file systems, and parsing.

Graphs A collection of nodes (vertices) connected by edges, representing relationships, widely used in networking, routing, and social networks.

Dynamic Programming An optimization technique that solves problems by breaking them into overlapping subproblems and storing their results.

Backtracking A problem-solving method that explores all possibilities recursively, backtracking when a solution is not feasible.

Sorting Algorithms Techniques for arranging elements in a specific order, such as quicksort, mergesort, and bubble sort, essential for data organization.

Searching Algorithms Methods for finding elements in a dataset, such as binary search, linear search, and graph traversal techniques.

Mathematics A field of study involving numbers, calculations, and logical reasoning, forming the foundation for algorithms and problem-solving.

Recursion A programming technique where a function calls itself to solve smaller instances of the same problem, often used in divide-and-conquer approaches.

Bit Manipulation Operations performed directly on binary representations of data, used for efficient computations and optimization tasks.