Given an number n, find the number of divisors whose at least one digit in the decimal representation matches with the number n.
Input : n = 10 Output: 2 Explanation: numbers are 1 and 10, 1 and 10 both have a nimbus of 1 digit common with n = 10. Input : n = 15 Output: 3 Explanation: the numbers are 1, 5, 15, all of them have a minimum of 1 digit common.
A naive approach is to iterate from 1 to n and check for all the divisors, and use hashing to determine if any of the digits match with n or not.
Time complexity: O(n)
Auxiliary space: O(1)
An efficient approach is to iterate from 1 to sqrt(n) and check for all the divisors i and n/i, if both are different, we check if there is any match for i and n/i, if yes we simply add 1 to the answer. We use hashing to store if a number is present or not.
Below is the implementation of the above approach
Time complexity: O(sqrt n)
Auxiliary Space: O(1)
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Improved By : Mithun Kumar