A laboratory database contains a sorted list of chemical elements:
Argon, Boron, Cobalt, Helium, Lithium, Neon, Oxygen, Sodium, Tin, Uranium, Xenon
A binary search algorithm is used to locate the target element "Boron".
Assume the list elements are indexed 1 to 11. The midpoint index at each stage is calculated using integer division (rounding down) as:
mid=floor(low+high2) \text{mid} = \text{floor}\left(\frac{\text{low} + \text{high}}{2}\right) mid=floor(2low+high)Complete the table to show the three elements, in order, that the algorithm would compare against the target value before locating "Boron".
| Step | Element |
|---|---|
| First | |
| Second | |
| Third | |
| Fourth | Boron |
159 exam-style questions on Edexcel GCSE Computer Science Algorithms, covering Constructs for solving problems, Variables, constants and data structures, Arithmetic, relational and logical operators, Tracing algorithm output with trace tables, Types of error and correcting logic errors, Standard algorithms (sorts and searches), and Evaluating algorithm fitness and efficiency. Each one has a worked solution and a mark scheme showing where the marks go.