872. Leaf-Similar Trees

1. Quesiton:

872. Leaf-Similar Trees

url: https://leetcode.com/problems/leaf-similar-trees/description/

Consider all the leaves of a binary tree.  From left to right order, the values of those leaves form a leaf value sequence.

For example, in the given tree above, the leaf value sequence is (6, 7, 4, 9, 8).

Two binary trees are considered leaf-similar if their leaf value sequence is the same.

Return true if and only if the two given trees with head nodes root1 and root2 are leaf-similar.

2. Soultion:

# Definition for a binary tree node.
class TreeNode(object):
    def __init__(self, x):
        self.val = x
        self.left = None
        self.right = None


class Solution(object):

    def inOrder(self, root, leaf_list):
        if root is None:
            return
        self.inOrder(root.left, leaf_list)
        if root.left is None and root.right is None:
            leaf_list.append(root.val)
        self.inOrder(root.right, leaf_list)

    def leafSimilar(self, root1, root2):
        """
        :type root1: TreeNode
        :type root2: TreeNode
        :rtype: bool
        """
        leaf_one = []
        leaf_two = []
        self.inOrder(root1, leaf_one)
        self.inOrder(root2, leaf_two)

        return leaf_one == leaf_two