236. 二叉树的最近公共祖先

236. 二叉树的最近公共祖先

• 难度: medium
• 原始链接: https://leetcode.cn/problems/lowest-common-ancestor-of-a-binary-tree
• 标签: 后序遍历

解法一: 后序遍历

go

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func lowestCommonAncestor(root, p, q *TreeNode) *TreeNode {
  if root == nil || root == p || root == q {
    return root
  }
  leftNode := lowestCommonAncestor(root.Left, p, q)
  rightNode := lowestCommonAncestor(root.Right, p, q)
  if leftNode == nil {
    return rightNode
  } else if rightNode == nil {
    return leftNode
  }
  return root
}