Skip to content

904. Leaf Similar Trees

Tree Depth-First Search Binary Tree

Problem - Leaf Similar Trees

Easy

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 = [1,2,3], root2 = [1,3,2]
Output: false

 

Constraints:

  • The number of nodes in each tree will be in the range [1, 200].
  • Both of the given trees will have values in the range [0, 200].

Solutions

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
# 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 leafSimilar(self, root1: Optional[TreeNode], root2: Optional[TreeNode]) -> bool:
        def dfs(root: Optional[TreeNode], arr):
            if root.left == root.right:
                arr.append(root.val)
                return

            if root.left:
                dfs(root.left, arr)
            if root.right:
                dfs(root.right, arr)

        arr1 = []
        arr2 = []
        dfs(root1, arr1)
        dfs(root2, arr2)
        return arr1 == arr2

Submission Stats:

  • Runtime: 0 ms (100.00%)
  • Memory: 17.7 MB (94.25%)