human
Product of nodes at k | Function to find product of digits of elements at k - th level.
Initialize result.
increasing level number.
decreasing level number.
check if current level is the desired level or not.
required product.
Driver program"
Solution in Python:
assistant
#Here is code to product of nodes at k and the other steps required.
 def productAtKthLevel ( tree , k ) :
	level = - 1
	product = 1
	n = len ( tree )
	for i in range ( 0 , n ) :
		if ( tree [ i ] == ' ( ' ) :
			level += 1
		elif ( tree [ i ] == ' ) ' ) :
			level -= 1
		else :
			if ( level == k ) :
				product *= ( int ( tree [ i ] ) - int ( '0' ) )
	return product
tree = " ( 0(5(6 ( ) ( ) ) ( 4 ( ) (9 ( ) ( ) ) ) ) ( 7(1 ( ) ( ) ) ( 3 ( ) ( ) ) ) ) "
k = 2
print ( productAtKthLevel ( tree , k ) )