Consider the following list.

list = {5, 11, 25, 28, 45, 78, 100, 120, 125};

Suppose that binary search as discussed in the book is used to determine whether 110 is in list. Exactly how many key comparisons are executed by binary search?

A) 3

B) 5

C) 8

D) 12

To search 110 is in list we key comparisons binary search will make are option

(A) 3

Explanation:

First the start = 0 and end = 8 and midindex=4.

So 110 will be compared to element at index 4 that is 45 since 110 is greater than 45 so start will be updated as start=midindex + 1.

start=5, end = 8 and midindex=6.

Element at index 6 is 100 so 110 will be compared to 100 since it is greater so again start will be updated midindex+1.

start=7, end=8 midindex=7

element at index 7 is 120 so 110 will be compared to 120 since it is smaller than 120 end will be updated as midindex - 1.

start=7, end=6

Now we have start > end. So the loop will finish execution.

Comparison made are 3.