LeetCode Problem : Convert Sorted List to Binary Search Tree

Problem

Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST.

Code

TreeNode *sortedListToBST_r(ListNode *p1,ListNode *p2) {
    if(p1 == p2)
        return 0;
    ListNode *curr1 = p1,*curr2 = p1;
    while(curr2->next != p2 && curr2->next->next != p2){
        curr2 = curr2->next->next;
        curr1 = curr1->next;
    }
    TreeNode *root = new TreeNode(curr1->val);
    root->left = sortedListToBST_r(p1,curr1);
    root->right = sortedListToBST_r(curr1->next,p2);
    return root;
}
TreeNode *sortedListToBST(ListNode *head) {
    // IMPORTANT: Please reset any member data you declared, as
    // the same Solution instance will be reused for each test case.
    return sortedListToBST_r(head,0);
}