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Special Prime Numbers in an Array Test | Pre-employment assessment - Testlify
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Special Prime Numbers in an Array Test

Overview of Special Prime Numbers in an Array Test

This coding test assesses a candidate's ability to program a small algorithm, testing their basic programming skills. using a short and straightforward coding task, this test helps you identify developers with essential coding skills.

Skills measured

  • Programming (Algorithms)

Available in



Coding Test


20 Mins





Use of Special Prime Numbers in an Array test

The question presents a problem where we are given an array of integers and are tasked with finding the first occurrence of a "special prime number" in the array. A "special prime number" is defined as a prime number that can be written as the sum of two numbers in the same array. The function find_special_prime should take in an array of integers arr and return the index of the first occurrence of a special prime number in the array. If a special prime number does not exist in arr, the function should return -1.

To solve this problem, we can use a combination of techniques. First, we need to iterate through the array and check each number to see if it is prime. If a number is prime, we then need to check if it can be written as the sum of two numbers in the same array. To check this, we can use a nested loop to iterate through the array again and check if the current prime number can be written as the sum of the current element and any previous element in the array. If we find a special prime number, we can return its index in the array. If we reach the end of the array without finding a special prime number, we can return -1.

Relevant for

  • Software Developer
  • Software Engineers
  • Software Programmer

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Programming (Algorithms)

In the Special Prime Numbers in an Array skill, learners will explore algorithms related to identifying and manipulating prime numbers within an array. This includes tasks such as finding the sum, product, and average of prime numbers, as well as determining the largest and smallest prime numbers in the array. Understanding these algorithms is crucial for developing strong problem-solving skills in programming, as prime numbers play a significant role in various mathematical and computational tasks. By mastering these concepts, learners will be better equipped to tackle complex programming challenges and optimize their code for efficiency and accuracy.

The Special Prime Numbers in an Array test is created by a subject-matter expert

Testlify’s skill tests are designed by experienced SMEs (subject matter experts). We evaluate these experts based on specific metrics such as expertise, capability, and their market reputation. Prior to being published, each skill test is peer-reviewed by other experts and then calibrated based on insights derived from a significant number of test-takers who are well-versed in that skill area. Our inherent feedback systems and built-in algorithms enable our SMEs to refine our tests continually.

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