Reduce the number to zero | Mitsogo

Mitsogo Question:

This mitsogo question is asked in the mitsogo 2nd round interview. To reduce the number to zero by using certain conditions.

Conditions:

Check whether the given number is prime or not.
If the number is prime then decrement the number by 1.
Otherwise, find the greatest prime number(GPN) which replaces the number.
Then replace the number by GPN.
Repeat the steps until the number became zero and count the number of steps taken.
At last, we have the output to reduce the number to zero

Explanation:

Let us consider input is 21
The given number is not prime, then check the greatest prime number(GPN) which divides 21.
And the GPN is 7, then replace 21 by 7 count is 1
Now 7 is a prime number then decrement the number to 6 count is 2. Then 6 is not prime.
The GPN which divides 6 is 3 then replace it count is 3.
Now 3 is a prime number then decrement to 2 and 2 is also a prime then decrement 1 count 5
At last, we get zero then print the count is 6

Program:

#include <stdio.h>
int isprime(int n)         //Check the number is prime or not
{
  int i;
  for(i=n/2;i>1;i--)
  {
    if(n%i==0)
    {
            return 0;     //return when the number not prime
    }
  }
    return 1;
}
int greatest_prime(int n) //Find the greatest prime number divide n
{
    int i,j;
    for(i=n/2;i>1;i--)
    {
        if(n%i==0)
        {
            j=isprime(i);  //check the divided number is prime or not
        }
        if(j==1)
        {
            return i;      //return greatest prime number
        }
    }
}
void main()
{
  int n,i,j=0;                 //j can count the number of steps taken to convert the number to zero
  printf("Enter the number:");
  scanf("%d",&n);
  while(n>0)
  {
    i=isprime(n);
    if(i==1)                 //If the number is prime then decrement the number by 1
    {
      n--;
      j++;
    }
    else                     //not prime number
    {
        i=greatest_prime(n);
      n=i;                //simplify number by replacing greatest prime number
      j++;
    }
    i=0;
  }
  printf("%d",j);
}

C Program For String Reversal | Samsung

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Interview Process:

1.aptutude test,2.logical reasoning,3.coding+essay writing
4.technical interview, all these rounds are elimination rounds, followed by 3 hr rounds.

Interview overview:

The aptitude round contains 60 questions with multiple choice.
Each wrong question carries a negative mark as well.
The logical round contains 2 problems which medium-difficult
HR round contains questions like tell me about your project? what is your favorite subject etc,

Vignesh