96. Unique Binary Search Trees - LeetCode Solution

class Solution:
    def numTrees(self, n: int) -> int:
        d = []
        d.append(1)
        
        for i in range(1, n+1):
            n = 0
            for j in range(i):
                n += d[j]*d[i-j-1]
            d.append(n)
            
            
        return d[len(d) -1 ]