查看“Binary tree”的源代码

[[Category:刷题]]
二叉树。

== 求深度的变种 ==

例如 LeetCode [https://leetcode.com/problems/balanced-binary-tree/ 110] 和 [https://leetcode.com/problems/diameter-of-binary-tree/ 543]，所求值和深度有关，所以在求深度的递归过程中进行一些操作。

=== LeetCode 543. Diameter of Binary Tree ===

树的直径为节点左右深度之和的最大值。便在计算深度时顺便遍历每个节点求最大的深度和，就为直径：
<syntaxhighlight lang=python>
def diameterOfBinaryTree(self, root: Optional[TreeNode]) -> int:
    diameter = 0
                                                                 
    def rec(root):
        nonlocal diameter
        if root is None:
            return 0
        left = rec(root.left)
        right = rec(root.right)
        diameter = max(diameter, left + right)
        return max(left, right) + 1
                                                                 
    rec(root)
    return diameter
</syntaxhighlight>