Lowest Common Ancestor of a Binary Tree LeetCode solution in C++

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class Solution {
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 public:
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  TreeNode *lowestCommonAncestor(TreeNode *root, TreeNode *p, TreeNode *q) {
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    if (!root) {
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      return NULL;
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    }
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    if (root == p or root == q) {
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      return root;
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    }
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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 and right) return root;
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    if (left)
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      return left;
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    else
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      return right;
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  }
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};