Given a non-negative number n. The problem is to check whether the given number n can be expressed as a product of single digit numbers or not.
Input : n = 24 Output : Yes Different combinations are: (8*3) and (6*4) Input : 68 Output : No To represent 68 as product of number, 17 must be included which is a two digit number.
Approach: We have to check whether the number n has no prime factors other than 2, 3, 5, 7. For this we repeatedly divide the number n by (2, 3, 5, 7) until it cannot be further divided by these numbers. After this process if n == 1, then it can be expressed as a product of single digit numbers, else if it is greater than 1, then it cannot be expressed.
Time Complexity: O(num), where num is the number of prime factors (2, 3, 5, 7) of n.
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Improved By : Sam007