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05: Finding the 2nd highest number in an array

Requirements gathering Does the array allow duplicates? If duplicates are allowed, then do you need to report duplicates? For example, in {2,4, 6, 3, 6, 5}, is 6 or 5 the second highest? Analysis If duplicates are not allowed, sort the array (Arrays.sort(…)) and get the second last element, …...

08: Write code to add, subtract, multiply, and divide given numbers?

A trivial coding example (i.e. a Calculator) tackled using the following programming paradigms in Java not only to perform well in coding interviews, but also to learn these programming paradigms.

Approach 1: Procedural Programming
Approaches 2 – 4: Object Oriented Programming
Approach 5: Functional Programming (Java 8)

Approach 1: Procedural

Output: result=13

Approach 2: OOP

When you have more mathematical operations,

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17 Java Coding Tips for job interviews and pre-interview coding tests

Java coding questions are very common in job interviews. Good coding skills are essentials for passing the peer code reviews with flying colors. Here are 17 coding tips with Java examples. Tip #1: If you are asked to write a function or code, … Read more ›...

Fibonacci number

Q1. Can you write a function to determine the nth Fibonacci number? The Fibonacci numbers under 2000 are : 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597. Where the zeroth number being 0, first number being 1, … Read more...

Fibonacci number with caching and Java 8 FP

Complimenting Fibonacci number coding – iterative and recursive approach, we can improve performance by caching. If you run this Output and you can see “fibonacci(3)” is repeated 2 times, “fibonacci(2)” is repeated 3 times, and so on. If you pick a larger number like 21, … Read more ›...

Find 2 numbers from an array that add up to the target

Q1. Given an array of integers, find two numbers such that they add up to a specific target number? For example, Given numbers: {2, 3, 8, 7, 5} Target number: 9 Result: 2 and 7 A1. Solution 1: Store processed numbers in a set. … Read more ›...

Find the first non repeated character in a given string input

Pseudocode 1) Precodnition check for null or empty input. 2) Loop throught the input string, and store each “character” as a key in a map with the value being the “character count”. For example, an input string of “stress” would have Key –Value s -3 t -1 r -1 e...

Finding the missing numbers Java example

Q. Can you write code to identify missing numbers in a given array of numbers?

Solution 1: Assuming that the given numbers are in order


The above solution assumes that the numbers are in order (i.e. sorted).

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Finding the perfect number

Q. Can you write code to output the perfect number between a given range? Definition: A perfect number is a positive integer that is equal to the sum of its proper divisors. The smallest perfect number is 6, which is the sum of 1, … Read more ›...

Fizz Buzz

Q1. Write a program that prints numbers from 1 to 30, but for multiples of three print “Fizz” instead of the number and for the multiples of five print “Buzz”. For numbers which are multiples of both three and five print “FizzBuzz”? A1. … Read more ›...

Generating random numbers in Java

Q1. Can you write Java code to generate random numbers between a given range? A1. E.g. 0 and 9 or 5 to 35, and so on. The “nextInt()” method works from “0” onwards. So, “rand.nextInt(9)” … Read more ›...

Huffman coding in Java

This is a very decent coding exercise to sharpen your coding skills. Nicely explained with diagrams and complete code. Q1. What is Huffman coding? A1. Huffman coding is a compression technique used to reduce the number of bits needed to send or store a message. … Read more ›...

Iteration Vs Recursion

Q1. Can you write a sample code that will count the number of “A”s in a given text “AAA rating“? Show both iterative and recursive approaches?


A for loop to traverse through each character of the String “AAA rating”,

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