binary_tree_search.c

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */
struct TreeNode* searchBST(struct TreeNode* root, int val) {
    if(root==NULL) return NULL;
    else if(root->val == val) return root;
    else if(val <= root->val) return searchBST(root->left, val);
    else return searchBST(root->right, val);
    
    return NULL;
}