Hey Guys, there was a question in Round 2 of the HackWithInfy Contest which I feel is quite nice and I wasn't able to think of any possible solution to it. So the question goes like that:-
We have defined a function f(x) = sum of all the digits of x. Now,
0 <= i <= N
0 <= j <= N
We have to count how many pairs are there which satisfy the condition that f(i) + f(j) is a prime.
Constraints:- 0 <= N <= 10^50
1) N = 2
pairs = 2
2) N = 3
pairs = 4
Can anyone suggest some possible method to solve this question??