Your task is to calculate sum of primes present as digits of given number N.
Example 1:
Input: 333
Output: 9
Explaination: 3 is a prime number. It
is present 3 times. So 3+3+3 = 9.
Example 2:
Input: 686
Output: 0
Explaination: Neither 6 nor 8 is a
prime number.
Your Task:
You do not need to read input or print anything. Your task is to complete the function primeSum() which takes N as input parameter and returns the sum of all the prime digits present in the number N.
Expected Time Complexity: O(logN)
Expected Auxiliary Space: O(1)
Constraints:
1 ≤ N ≤ 5*10^{4}

见题面

见题面