Question

Binary search is harder to implement than it looks. ‘Although the basic idea of binary search is comparatively straightforward, the details can be surprisingly tricky…’ — Donald Knuth.

Which bugs are most likely to be introduced into a new binary search implementation?

Answer 1

Here are some I can think of:

• Off-by-one errors, when determining the boundary of the next interval
• Handling of duplicate items, if you are suppose to return the first equal item in the array but instead returned a subsequent equal item
• Numerical underflows/overflows when computing indices, with huge arrays
• Recursive vs non-recursive implementation, a design choice you should consider

Are these what you have in mind?