Prime Visits test cases failed

#1

Why my test cases 1 and 2 failed

#2

@shardul15,
https://ide.codingblocks.com/s/261257 corrected code

Your code was throwing index out of bounds exception incase a=0.

In the line:

			int x = csum[b] - csum[a - 1];

if a=0, then csum[-1] is an invalid call

#3

thanks @sanchit.bansal06