Fizz Buzz

 Posted on April 3, 2014  (Last modified on August 7, 2020)  |  2 minutes  |  Kinshuk Chandra

Problem Write a program that prints the numbers from 1 to 100. 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” Example of sequence - 3,6,9,12,15,18,1,24,27. Solution Method 1- Brute force Here we notice that that after 15, there is 18. So, we should increment the iterator by 2, and then 1 i. [Read More]
kodeknight  prime  prime-factor  factorization 

Fizz Buzz

 Posted on April 3, 2014  (Last modified on August 11, 2020)  |  2 minutes  |  Kinshuk Chandra

Problem Write a program that prints the numbers from 1 to 100. 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” Example of sequence - 3,6,9,12,15,18,1,24,27. Solution Method 1- Brute force Here we notice that that after 15, there is 18. So, we should increment the iterator by 2, and then 1 i. [Read More]
kodeknight  prime  prime-factor  factorization 

Sieve of Atkins

 Posted on March 25, 2014  (Last modified on August 7, 2020)  |  5 minutes  |  Kinshuk Chandra

Problem Given a number n, print all primes smaller than or equal to n. Example For example, if n is 10, the output should be “2, 3, 5, 7″. If n is 20, the output should be “2, 3, 5, 7, 11, 13, 17, 19″. Algorithm We have discussed sieve of Eratosthenes here, but lets move to the Sieve of Atkins algorithm today which is a modified version of sieve of Eratosthenes. [Read More]
kodeknight  prime 

Algorithm to find out number of factors of a number

 Posted on March 25, 2014  (Last modified on August 7, 2020)  |  2 minutes  |  Kinshuk Chandra

Problem Given a number find the number of factors of that number Example Factors of 18 are 1, 2, 3, 6, 9, 18. Hence 6 factors. Solution Method 1 - Using divisor function. Let n be the given number. If n = p1^e1 * p2^e2 * ... * pk^ek, where each p is a prime number, then the number of factors of n is (e1 + 1)*(e2 + 1)* . [Read More]
kodeknight  prime  prime-factor  factorization 

Program to print all prime factors of a given number

 Posted on March 25, 2014  (Last modified on August 7, 2020)  |  2 minutes  |  Kinshuk Chandra

Problem Given a number n, write an efficient function to print all prime factors of n.  Example For example, if the input number is 12, then output should be “2 2 3″. And if the input number is 315, then output should be “3 3 5 7″. Following are the steps to find all prime factors. 1) While n is divisible by 2, print 2 and divide n by 2. [Read More]
factor  kodeknight  prime  prime-factor  factorization 

To find the list of primes till N

 Posted on March 24, 2014  (Last modified on August 7, 2020)  |  1 minutes  |  Kinshuk Chandra

Problem Given a number n, print all primes smaller than or equal to n. Example For example, if n is 10, the output should be “2, 3, 5, 7″. If n is 20, the output should be “2, 3, 5, 7, 11, 13, 17, 19″. Solution Method 1 - Brute force We just loop till number N, and check if individual iterator is prime or not. Code : [Read More]
kodeknight  prime 

Sieve of Eratosthenes

 Posted on March 24, 2014  (Last modified on August 7, 2020)  |  4 minutes  |  Kinshuk Chandra

Problem Given a number n, print all primes smaller than or equal to n. It is also given that n is a small number. Example For example, if n is 10, the output should be “2, 3, 5, 7″. If n is 20, the output should be “2, 3, 5, 7, 11, 13, 17, 19″. Algorithm The sieve of Eratosthenes is one of the most efficient ways to find all primes smaller than n when n is smaller than 10 million or so (Ref Wiki). [Read More]
kodeknight  prime 

Efficient ways to check if number is prime number

 Posted on March 24, 2014  (Last modified on August 7, 2020)  |  4 minutes  |  Kinshuk Chandra

Problem How to check if number is prime or not You may remember that a prime number is one whose only factors are itself and 1. Other numbers are called oblong numbers (they can be represented as an oblong of dots) or composite numbers. If you have a number and you want to find out if it’s prime, that is called performing a primality test. The naive approach is to check all numbers m from 2 to sqrt(n) and verify that n % m is not 0. [Read More]
kodeknight  prime 

Prove that number between twin primes is divided by 6

 Posted on December 18, 2011  (Last modified on August 7, 2020)  |  1 minutes  |  Kinshuk Chandra

A Twin Prime number is a prime number which differs from other prime number by two. eg (5,7), (11,13), (17,19), (29,31), (41,43), (59,61)…….. Prove that number between twin primes is divisible by 6. Solution 1: all prime numbers are of the form 6x+1 or 6x-1 so to be twin primes they should be 6x-1 and 6x+1 for some x so the number netween them is 6x which is divided by 6 [Read More]
kodeknight  twin-prime  prime 

Find the nth Ugly Number

 Posted on April 10, 2010  (Last modified on August 7, 2020)  |  4 minutes  |  Kinshuk Chandra

Problem Ugly numbers are numbers whose only prime factors are 2, 3 or 5. The sequence 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, … shows the first 11 ugly numbers. …By convention, 1 is included. Write a program to find and print the 1500’th ugly number.   Solution Method 1 - Brute force Loop for all positive integers until ugly number count is smaller than n, if an integer is ugly than increment ugly number count. [Read More]
kodeknight  series  Special Nos.  prime  programming Questions  ugly-number  prime-factor  factorization