235-Lowest-Common-Ancestor-of-a-Binary-Search-Tree.c

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */
struct TreeNode* lowestCommonAncestor(struct TreeNode* root, struct TreeNode* p, struct TreeNode* q) {
    struct TreeNode *tempNode;
    while (NULL != root)
    {
        if (p->val < root->val && q->val < root->val)
        {
            root = root->left;
        }
        else if (p->val > root->val && q->val > root->val)
        {
            root = root->right;
        }
        else
        {
            return root;
        }
    }
    return root;
}