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// @Title: 二叉树的最近公共祖先 (二叉树的最近公共祖先 LCOF)
// @Author: 15816537946@163.com
// @Date: 2022-02-20 23:57:59
// @Runtime: 4 ms
// @Memory: 7.4 MB
/**
 * 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
    }

    left := lowestCommonAncestor(root.Left,p,q)
    right := lowestCommonAncestor(root.Right,p,q)

    if left == nil {
        return right
    }
    if right == nil {
        return left
    }
    
    return root

}