How do you implement binary search on a sorted array efficiently?
This coding problem requires you to write an algorithm to find an element's index or return -1 if not found, testing your logic and edge case handling.
Why Interviewers Ask This
Binary search is a classic algorithm that demonstrates a candidate's ability to optimize search operations from linear to logarithmic time. Interviewers look for clean implementation, correct boundary conditions, and the ability to handle cases where the element is not present. It also tests basic proficiency in array manipulation and loop control.
How to Answer This Question
Clearly state the prerequisites: the array must be sorted. Initialize low and high pointers. Loop while low is less than or equal to high. Calculate the mid-point and compare with the target. Adjust pointers based on the comparison. Handle edge cases like empty arrays or single elements explicitly before coding.
Key Points to Cover
- Sorted array requirement
- Low and high pointer initialization
- Mid-point calculation logic
- Pointer adjustment strategy
Sample Answer
To implement binary search, I first ensure the array is sorted. I initialize two pointers, low at the start and high at the end. While low is less than or equal to high, I calculate the middle index. If the middle elemen…
Common Mistakes to Avoid
- Infinite loops due to incorrect pointer updates
- Integer overflow in mid calculation
- Ignoring off-by-one errors
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