Let T be a full binary tree with 8 leaves. (A full binary tree has every level full). Suppose two leaves a and b of T are chosen uniformly and independently at random. The expected value of the distance between a and b in T (i.e., the number of edges in the unique path between a and b) is (rounded off to 2 decimal places) _____.

Consider the following $$New-order$$ strategy for traversing a binary tree:

$$\,\,\,\,\,\,\, \bullet \,\,\,\,\,$$ Visit the root;
$$\,\,\,\,\,\,\, \bullet \,\,\,\,\,$$ Visit the right subtree using $$New-order;$$
$$\,\,\,\,\,\,\, \bullet \,\,\,\,\,$$ Visit the left subtree using $$New-order;$$

The New-order traversal of the expression tree corresponding to the reverse polish expression 3 4 * 5 - 2 ^ 6 7 * 1 + - is given by:

The number of ways in which the numbers $$1, 2, 3, 4, 5, 6, 7$$ can be inserted in an empty binary search tree, such that the resulting tree has height $$6,$$ is _____________.

$$Note:\,\,\,The\,\,height\,\,of\,\,a\,tree\,\,with\,\,a\,\,\sin gle\,\,node\,\,is\,\,0$$

Suppose we have a balanced binary search tree T holding n numbers. We are given two numbers L and H and wish to sum up all the numbers in T that lie between L and H. Suppose there are m such numbers in T. If the tightest upper bound on the time to compute the sum is O( n^a log^b n + m^c log^d n ), the value of a + 10b + 100c + 1000d is _______.