Let P(x) be a function that returns the product of digits of x. For example P(935) = 9*3*5 = 135. Now let us define another function P_repeat(x):
int P_repeat(int x){
if(x < 10) return x
return P_repeat(P(x))
}
For a value v, ind the number of numbers x less than N such that P_repeat(_x_) = v.
How would I make a transition between states in a digit DP for this problem?
Please help, and thanks in advance!