Describe an algorithm Find-Inversion(A) that takes as input an array A and finds an inversion in O(n) time. code example

Example 1: a recursive function that calculates the greatest common divisor from user's input in java

/**
 * Java program to demonstrate How to find Greatest Common Divisor or GCD of 
 * two numbers using Euclid’s method. There are other methods as well to 
 * find GCD of two number in Java but this example of finding GCD of two number
 * is most simple.
 *
 * @author Javin Paul
 */
public class GCDExample {
  
  
    public static void main(String args[]){
     
        //Enter two number whose GCD needs to be calculated.      
        Scanner scanner = new Scanner(System.in);
        System.out.println("Please enter first number to find GCD");
        int number1 = scanner.nextInt();
        System.out.println("Please enter second number to find GCD");
        int number2 = scanner.nextInt();
      
        System.out.println("GCD of two numbers " + number1 +" and " 
                           + number2 +" is :" + findGCD(number1,number2));
      
      
    }

    /*
     * Java method to find GCD of two number using Euclid's method
     * @return GDC of two numbers in Java
     */
    private static int findGCD(int number1, int number2) {
        //base case
        if(number2 == 0){
            return number1;
        }
        return findGCD(number2, number1%number2);
    }
  
}

Output:
Please enter first number to find GCD
54
Please enter second number to find GCD
24
GCD of two numbers 54 and 24 is :6

Example 2: Write a function called square_odd that has one parameter. Your function must calculate the square of each odd number in a list. Return a Python 3 list containing the squared values Challenge yourself: Solve this problem with a list comprehension!

nums = [square_odds**2 for square_odds in nums if square_odds%2 != 0]

Example 3: create a function that takes in an array of numbers and returns only the number that are even after 1 is added to the value

const evenAfter = (arr) => {
    let i = 0
    let newArr = []
    while (i <= arr.length) {
        if ((arr[i] + 1) % 2 === 0){          
            newArr.push(arr[i])
        }  
        i++
    }
    return newArr
}

console.log(evenAfter([3,6,7,8,9,11]))