How To Uncovering Largest Prime Number Element Of A Lay Out Inwards Coffee - Programming Kata

One of the mutual programming kata to acquire coding is write a plan to discovery the largest prime gene of a number. Like whatever other programming problem, y'all demand to cook the logic to solve this problem. Before solving the problem, let's revise the concept of discover theory. Prime factors of a positive integer are the prime numbers that split the discover precisely i.e. without whatever remainder, in addition to prime factorization is the procedure of finding all prime numbers when multiply together brand master copy number.  A positive integer tin dismiss conduct maintain multiple prime factors, our challenge is to discovery the largest prime gene of a number. For example, half-dozen has 2 prime factors 2 in addition to 3, your plan should supply 3, because that's the largest prime factors. In i of earlier problem, nosotros conduct maintain learned how to discovery prime gene of a discover inwards Java in addition to nosotros volition role the similar logic here, simply instead of returning a listing of prime factors nosotros volition entirely supply the largest prime factor.

Java Program to Find Largest Prime Factor of an Integer

Problem : Write a plan to discovery the largest prime gene of a positive integer inwards Java. If nosotros overstep fifteen to your program, it should supply 5, in addition to if nosotros overstep half-dozen to your plan it should supply 3.

Solution : As nosotros learned a discover is called prime gene if it is prime discover in addition to it tin dismiss split the discover exactly. Another belongings of prime gene is that if nosotros proceed dividing the discover yesteryear prime gene in addition to hence it volition either fully split the discover or attain about other prime gene e.g. if nosotros demand to discovery the prime factors of xvi in addition to hence starting from 2 if proceed dividing, eventually dividend overstep 1, hence 2 is the entirely prime gene of 16. On other manus if demand to discovery prime gene of 15, in addition to hence nosotros outset seek to split it yesteryear 2, simply since its non divisible yesteryear 2, nosotros motility to adjacent discover which is 3. Since three tin dismiss split 15, it produces about other prime discover 5, directly v is non divisible yesteryear anything other than 5, hence three in addition to v overstep prime gene of 15.

Algorithm : In our program, nosotros conduct maintain used the same logic. We start alongside 2, the smallest prime discover in addition to seek to split the number, if discover is divisible in addition to hence nosotros proceed dividing it yesteryear same discover until its non divisible whatever more. Now nosotros motility to adjacent number, the largest discover which is able to fully split the input is our largest prime factor. This would endure to a greater extent than clear when y'all encounter the actual program.

import java.util.Random; import java.util.Scanner;  /** * Java plan to discovery in addition to impress largest prime gene of an integer number. for * lawsuit discover half-dozen has 2 prime factors 2 in addition to 3, simply three is the largest prime * gene of 6. input fifteen output v * * @author Javin Paul */ public class LargetPrimeFactor{      public static void main(String args[]) {          System.out.printf("Largest prime gene of discover '%d' is %d %n",                 6, largestPrimeFactor(6));         System.out.printf("highest prime gene of discover '%d' is %d %n",                 15, largestPrimeFactor(15));         System.out.printf("Biggest prime gene of discover '%d' is %d %n",                 392832, largestPrimeFactor(392832));         System.out.printf("Largest prime gene of discover '%d' is %d %n",                 1787866, largestPrimeFactor(1787866));     }      /**      * @return largest prime gene of a discover      */     public static int largestPrimeFactor(long number) {         int i;         long copyOfInput = number;          for (i = 2; i <= copyOfInput; i++) {             if (copyOfInput % i == 0) {                 copyOfInput /= i;                 i--;             }         }          return i;     }  }  Output: Largest prime gene of discover '6' is 3 highest prime gene of discover '15' is 5 Biggest prime gene of discover '392832' is 31 Largest prime gene of discover '1787866' is 893933

You tin dismiss encounter from output that our plan is working properly, for half-dozen the largest prime gene is three in addition to for fifteen its 5. Here is our unit of measurement bear witness to cheque twosome of to a greater extent than numbers :

import static org.junit.Assert.assertEquals;  import org.junit.Test;  public class LargestPrimeFactorTest {              @Test     public void testLargestPrimeFactors(){         assertEquals(2, HelloWorld.largestPrimeFactor(2));         assertEquals(3, HelloWorld.largestPrimeFactor(6));         assertEquals(5, HelloWorld.largestPrimeFactor(15));         assertEquals(7, HelloWorld.largestPrimeFactor(147));         assertEquals(17, HelloWorld.largestPrimeFactor(17));         assertEquals(31, HelloWorld.largestPrimeFactor(392832));         assertEquals(893933, HelloWorld.largestPrimeFactor(1787866));     }          }

in addition to hither is the bear witness result, y'all tin dismiss encounter the bear witness passed successfully.

One matter to banking corporation annotation hither is that nosotros are non treatment invalid input hither e.g. 0, 1 or negative number, which nosotros should if this enquiry is asked on Interview. You tin dismiss throw IllegalArgumentException for those inputs which are non valid equally per work specification. Similarly, y'all likewise demand to include unit of measurement bear witness to cheque those invalid inputs. I acquire out that business for y'all equally practice.


That's all nearly how to discovery largest prime gene of a discover inwards Java. This is a actually skilful exercise to acquire coding when y'all are starting alongside Java or Python or whatever other programming language. This form of work volition assistance to cook your programming logic in addition to better your coding skill. Believe me, its non tardily to convert a existent life algorithm into plan without practice. You must solve about basic coding work based upon String, array in addition to recursion to acquire gibe of coding. I conduct maintain shared many such exercise inwards this blog, if y'all are interested y'all tin dismiss likewise accept a await at next listing of work :

• How to Swap Two Numbers without using Temp Variable inwards Java? (Trick)
• Write a plan to cheque if LinkedList contains loop inwards Java? (Solution)
• How to take duplicates from array without using Collection API? (Solution)
• How to calculate Sum of Digits of a discover inwards Java? (Solution)
• Write a Program to Check if a discover is Power of Two or not? (Answer)
• Write a business office to discovery middle chemical constituent of LinkedList inwards i pass? (See here for Solution)
• How to discovery outset non repeated characters from String inwards Java? (See here for solution)
• How to cheque if a discover is binary inwards Java? (Solution)
• Write a plan to cheque if a discover is Prime or not? (Solution)
• How to discovery Fibonacci Series of a Given Number? (Solution)
• Write a method to cheque if 2 String are Anagram of each other? (Solution)
• Write a method to count occurrences of  a graphic symbol inwards String? (Solution)
• How to cheque if a discover is Armstrong discover or not? (Solution)
• Write a method to take duplicates from ArrayList inwards Java? (Solution)
• How to preclude Deadlock inwards Java? (Click here for solution)
• Howto solve Producer Consumer Problem inwards Java. (Solution)
• Write a plan to cheque if a discover is Palindrome or not? (Solution)
• Write a plan to cheque if Array contains duplicate discover or not? (Solution)
• How to contrary String inwards Java without using API methods? (Solution)
• How to calculate factorial using recursion inwards Java? (Click here for solution)

Further Learning
The Coding Interview Bootcamp: Algorithms + Data Structures
Data Structures in addition to Algorithms: Deep Dive Using Java
Algorithms in addition to Data Structures - Part 1 in addition to 2

Share this post