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05: Finding the 2nd highest number in an array in Java

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, which executes in O(nlogn)
If duplicates are allowed, loop through each element have two variables to store highest & second highest values.

…

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

public interface Calculate {
   abstract int calculate(int operand1, int oerand2, Operator operator);
}

public interface Calculate {

abstract int calculate(int operand1, int oerand2, Operator operator);

}

public enum Operator {
   ADD, SUBTRACT, DIVIDE, MULTIPLY;
}

public enum Operator {

ADD, SUBTRACT, DIVIDE, MULTIPLY;

}

public class CalculateImpl implements Calculate {

    @Override
    public int calculate(int operand1, int operand2, Operator operator) {

        switch (operator) {
        case ADD:
            return operand1 + operand2;
        case SUBTRACT:
            return operand1 - operand2;
        case MULTIPLY:
            return operand1 * operand2;
        case DIVIDE:
            return operand1 / operand2;
        }

        throw new RuntimeException(operator + "is unsupported");
    }

}

public class CalculateImpl implements Calculate {

@Override

public int calculate(int operand1, int operand2, Operator operator) {

switch (operator) {

case ADD:

return operand1 + operand2;

case SUBTRACT:

return operand1 - operand2;

case MULTIPLY:

return operand1 * operand2;

case DIVIDE:

return operand1 / operand2;

}

throw new RuntimeException(operator + "is unsupported");

}

public class CalculatorTest {
    public static void main(String[] args) {
       Calculate calc = new CalculateImpl();
       int result = calc.calculate(5,6,Operator.ADD);

…

17 Java coding interview questions – tips & considerations

Java coding interview questions are very common in job interviews. Good coding skills are essentials for passing the peer code reviews with flying colours. Here are 17 coding tips with Java examples.

Tip #1: If you are asked to write a function or code, make sure that your code fails fast.…

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,…

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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

 public class RecursiveFibonacci {

  public int fibonacci(int n) {
    if (n == 0 || n == 1)
      return n;

    System.out.println("evaluating fibonacci(" + n + ")");
    return fibonacci(n - 2) + fibonacci(n - 1);
  }

  public static void main(String[] args) {
      int nThfibonacciNo = new RecursiveFibonacci().fibonacci(5);

…

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:…

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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…

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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

public class MissingNumber {

    public static void main(String[] args) {
        int numbers[] = { 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 18 };
        new MissingNumber().findMissingNumbers(numbers,

…

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…

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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”….

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Blog Archives

05: Finding the 2nd highest number in an array in Java

Requirements gathering

Analysis

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

Approach 1: Procedural

17 Java coding interview questions – tips & considerations

Fibonacci number

Members Only Content

Fibonacci number with caching and Java 8 FP

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

Members Only Content

Find the first non repeated character in a given string input

Members Only Content

Finding the missing numbers Java example

Finding the perfect number

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Fizz Buzz

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