LeetCode "Flatten Binary Tree to Linked List"

Really interesting BST manipulation problem!

class Solution {
public:
    TreeNode *findConn(TreeNode *p)
    {
        TreeNode *pTmp = p;
        while (pTmp->right)
        {
            pTmp = pTmp->right;
        }
        return pTmp;
    }
    void flatten(TreeNode *root) {
        if (!root) return;
        TreeNode *p = root;
        while (p)
        {
            if (!p->left && !p->right) break;    //    end
            if (p->left && !p->right)
            {
                p->right = p->left;
                p->left = NULL;
            }
            if (p->left && p->right)
            {
                TreeNode *pTmpRight = p->right;
                TreeNode *pConn = findConn(p->left);
                p->right = p->left;
                pConn->right = pTmpRight;
                p->left = NULL;
            }
            p = p->right;
        }        
    }
};