Find Leaves of Binary Tree

Author: anantkaushik

366-find-leaves-of-binary-tree.py

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+"""
+Problem Link: https://leetcode.com/problems/find-leaves-of-binary-tree/
+
+Given the root of a binary tree, collect a tree's nodes as if you were doing this:
+Collect all the leaf nodes.
+Remove all the leaf nodes.
+Repeat until the tree is empty.
+
+Example 1:
+Input: root = [1,2,3,4,5]
+Output: [[4,5,3],[2],[1]]
+Explanation:
+[[3,5,4],[2],[1]] and [[3,4,5],[2],[1]] are also considered correct answers since per 
+each level it does not matter the order on which elements are returned.
+
+Example 2:
+Input: root = [1]
+Output: [[1]]
+
+Constraints:
+The number of nodes in the tree is in the range [1, 100].
+-100 <= Node.val <= 100
+"""
+# Definition for a binary tree node.
+# class TreeNode:
+# def __init__(self, val=0, left=None, right=None):
+# self.val = val
+# self.left = left
+# self.right = right
+class Solution:
+ def findLeaves(self, root: Optional[TreeNode]) -> List[List[int]]:
+ leaves = []
+ self.get_height(root, leaves)
+ return leaves
+ 
+ def get_height(self, root, leaves):
+ if not root:
+ return -1
+ 
+ height = 1 + max(self.get_height(root.left, leaves),
+ self.get_height(root.right, leaves))
+ if height > len(leaves) - 1:
+ leaves.append([])
+ 
+ leaves[height].append(root.val)
+ 
+ return height