How to take the startiing range and ending range

#1

I got the approach of solving this problem using sieve of Eratosthenes
but I am not getting how to apply the starting range and the ending range to the same.

#2

Make a cumulative count array of the prime sieve and then answer is count[b] - count [a]

#3

I have got the range
but the thing is I am still getting all the test cases wrong

#4

Please post your code

#5

Scanner sc=new Scanner(System.in);
int a=0;
int b=11;
int n=b-a;
int count=0;

if(a>1)
{
	
	int[] arr=new int[n+1];

for(int i=0;i<arr.length;i++)
{
	
	
		
	
	for(int j=i;j<=i;j++)
	{
		arr[j]=a;
		a++;
	}
}
for(int i=0;i<arr.length;i++)
{
	System.out.println(arr[i]);
}
for(int i=0;i<arr.length;i++)
{
	boolean flag=true;
	for(int divisor=2;divisor<arr[i];divisor++)
	{
		if(arr[i]%divisor==0)
		{
			flag=false;
		}
	}
	if(flag==true)
	{
		count++;
	
	}

}
System.out.println(count);

}

else if(a==0)
{
int[] arr=new int[n];
a=a+2;
for(int i=0;i<arr.length;i++)
{
for(int j=i;j<=i;j++)
{
arr[j]=a;
a++;
}
}
for(int i=0;i<arr.length;i++)
{
System.out.println(arr[i]);
}
for(int i=0;i<arr.length;i++)
{
boolean flag=true;
for(int divisor=2;divisor<arr[i];divisor++)
{
if(arr[i]%divisor==0)
{
flag=false;

	 }
 }
 if(flag==true)
 {
	 count++;
 }

}
System.out.println(count);
}
else
{
int[] arr=new int[n];
a=a+1;
for(int i=0;i<arr.length;i++)
{
for(int j=i;j<=i;j++)
{
arr[j]=a;
a++;
}
}
for(int i=0;i<arr.length;i++)
{
System.out.println(arr[i]);
}
for(int i=0;i<arr.length;i++)
{
boolean flag=true;
for(int divisor=2;divisor<arr[i];divisor++)
{
if(arr[i]%divisor==0)
{
flag=false;

		 }
	 }
	 if(flag==true)
	 {
		 count++;
	 }
 }
 System.out.println(count);

}
}
}

#6

I have even tried it with sieve of Eratosthenes but its showing me an error

#7

What exactly have you done in this code ? Why are you printing the initial array ?

#8

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