all-possible-full-binary-trees.py

# https://leetcode.com/problems/all-possible-full-binary-trees/

class Solution:
    def allPossibleFBT(self, N: int) -> List[TreeNode]:

        trees = []

        if N>0:
        
            for _ in range(N+1):
                trees.append([])

            trees[1].append(TreeNode(0))

            for r in range(1, N+1, 2):
                for l in range(1, r, 2):
                    for node_l in trees[l]:
                        for node_r in trees[r-l-1]:
                            
                            root = TreeNode(0)
                            
                            root.left = node_l
                            root.right = node_r
                            
                            trees[r].append(root)
            
            return trees[N]
        
        else :
            return trees