872. Leaf-Similar Trees
Đề Bài
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].
Thuật Toán & Kỹ Thuật
⏱️ Thời gian
O(V+E)
💾 Không gian
O(V)
Lời Giải
Python
0872-leaf-similar-trees.py
# 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 dfs(self, root):
if not root:
return []
if not (root.left or root.right):
return [root.val]
return self.dfs(root.left) + self.dfs(root.right)
def leafSimilar(self, root1: Optional[TreeNode], root2: Optional[TreeNode]) -> bool:
return self.dfs(root1) == self.dfs(root2)