Lowest Common Ancestor of a Binary Tree, with Parent Pointer

Given a binary tree, find the lowest common ancestor of two given nodes in tree. Each node contains a parent pointer which links to its parent.

int getHeight(Node* p)
{
int height = 0;
while (p)
{
height++;
p = p->parent;
}
return height;
}

Node* LCA(Node* p, Node *q)
{
int h1 = getHeight(p);
int h2 = getHeight(q);
if (h1 > h2)
{
swap(h1, h2);
swap(p, q);
}
for (int h = 0; h < h2-h1; h++)
{
q = q->parent;
}
while (p && q)
{
if (p == q)
return p;
p = p->parent;
q = q->parent;
}
return NULL;
}