Given an integer A, how many structurally unique BST’s (binary search trees) exist that can store values 1…A?
Input Format:
The first and the only argument of input contains the integer, A.
Output Format:
Return an integer, representing the answer asked in problem statement.
Constraints:
1 <= A <= 18
Example:
Input 1:
A = 3
Output 1:
5
Explanation 1:
1 3 3 2 1
\ / / / \ \
3 2 1 1 3 2
/ / \ \
2 1 2 3
NOTE: You only need to implement the given function. Do not read input, instead use the arguments to the function. Do not print the output, instead return values as specified. Still have a question? Checkout Sample Codes for more details.