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// Recursive
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class Solution {
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 public:
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  TreeNode *searchBST(TreeNode *root, int &val) {
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    if (root == NULL) return NULL;
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    if (root->val == val) return root;
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    if (root->val > val) return searchBST(root->left, val);
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    return searchBST(root->right, val);
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  }
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};
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// Iterative
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class Solution {
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 public:
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  TreeNode *searchBST(TreeNode *root, int val) {
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    while (root) {
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      if (root->val == val) return root;
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      root = root->val > val ? root->left : root->right;
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    }
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    return NULL;
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  }
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};