236.二叉树的最近公共祖先.go

/*
 * @lc app=leetcode.cn id=236 lang=golang
 *
 * [236] 二叉树的最近公共祖先
 */

// @lc code=start
/**
 * Definition for TreeNode.
 * type TreeNode struct {
 *     Val int
 *     Left *ListNode
 *     Right *ListNode
 * }
 */
 func lowestCommonAncestor(root, p, q *TreeNode) *TreeNode {
	if root == nil {
		return root
	}
	if root == p || root == q {
		return root
	}
	left := lowestCommonAncestor(root.Left, p, q)
	right := lowestCommonAncestor(root.Right, p, q)
	if left != nil && right != nil {
		return root
	}
	if left != nil {
		return left
	}
	if right != nil {
		return right
	}
	return nil
}
// @lc code=end