【LeetCode 235_二叉搜索树】Lowest Common Ancestor of a Binary Search Tree

TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q)
{
if (root == NULL || p == NULL || q == NULL)
return NULL;

if (root->val > p->val && root->val > q->val)
return lowestCommonAncestor(root->left, p, q);
else if (root->val < p->val && root->val < q->val)
return lowestCommonAncestor(root->right, p, q);
return root;
}

TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q)
{
if (root == NULL || p == NULL || q == NULL)
return NULL;

while (true) {
if (root->val < p->val && root->val < q->val)
root = root->right;
else if (root->val > p->val && root->val > q->val)
root = root->left;
else
break;
}
return root;
}