Complete the code to find how many pairs of whole numbers add exactly to n but only consider numbers between a and b inclusive. display the number of pairs only. example 1: a = 0, b = 10 and n = 17 has 2 pairs which 7, 10 and 8, 9. (note that 10, 7 and 9, 8 don’t count as extra pairs! ) example 2: a = −5, b = 5 and n = 2 has 5 pairs which are −3, 5, −2, 4, −1, 3, 0, 2, and 1, 1. a = input ('enter low value in range : '); b = input ('enter high value in range : '); n = input ('enter any whole number : ');

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?