# 872. Leaf-Similar Trees

# 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.

# Example 1:
# Input: root1 = [3,5,1,6,2,9,8,null,null,7,4], root2 = [3,5,1,6,7,4,2,null,null,null,null,null,null,9,8]
# Output: true

# Example 2:
# Input: root1 = [1], root2 = [1]
# Output: true

# Example 3:
# Input: root1 = [1], root2 = [2]
# Output: false

# Example 4:
# Input: root1 = [1,2], root2 = [2,2]
# Output: true

# Example 5:
# Input: root1 = [1,2,3], root2 = [1,3,2]
# Output: false

# Definition for a binary tree node.


class TreeNode(object):
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right


class Solution(object):
    def leafSimilar(self, root1, root2):
        def dfs(root, rs):
            if not root:
                return
            if not root.left and not root.right:
                rs.append(root.val)
            dfs(root.left, rs)
            dfs(root.right, rs)

        leaf1 = []
        dfs(root1, leaf1)

        leaf2 = []
        dfs(root2, leaf2)

        return leaf1 == leaf2
