Lowest Common Ancestor of a Binary Search Tree LeetCode solution in Java

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/**
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 * Definition for a binary tree node. public class TreeNode { int val; TreeNode left; TreeNode
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 * right; TreeNode(int x) { val = x; } }
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 */
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class Solution {
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  public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
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    if (root == null || root == p || root == q) return root;
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    TreeNode left = lowestCommonAncestor(root.left, p, q);
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    TreeNode right = lowestCommonAncestor(root.right, p, q);
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    if (left == null) return right;
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    if (right == null) return left;
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    else {
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      return root;
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    }
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  }
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}