<|im_start|>system
You are a helpful AI assistant.<|im_end|>
<|im_start|>user
What is a binary search algorithm?<|im_end|>
<|im_start|>assistant
A binary search algorithm is a search algorithm that works by dividing a sorted list into two equal parts and repeatedly comparing the middle element of each part with the target value. If the middle element is equal to the target value, the search is successful. If the middle element is greater than the target value, the search continues in the lower half of the list. If the middle element is less than the target value, the search continues in the upper half of the list. This process is repeated until the target value is found or until the search is narrowed down to an empty sub-list, indicating that the target value is not present in the original list. Binary search algorithms are very efficient for searching large, sorted lists and can quickly find the target value with only a few comparisons.<|im_end|>
<|im_start|>user
Is it useful with unsorted data?<|im_end|>
<|im_start|>assistant
No, binary search needs a sorted array. You might have other properties of an array that enables you to make a search that is more efficient than a mere iteration but the very nature of binary search necessitates sorted data.

If you know that part of your array is sorted you might extract that, of course, execute a binary search there and exclude this from the otherwise linear search.<|im_end|>
<|im_start|>user
Does it work on strings?<|im_end|>
<|im_start|>assistant
Certainly. It works on letters, strings, and string arrays.<|im_end|>