## Binary Search for Upper Bound

A frequent question I ask when interviewing some candidates is binary search. It cannot be more easier to write a binary search, but the variant may be challenging. For example, upper bound for the given target. When should I shrink my scope to left? This post elucidates the steps of binary search by illustrating some common mistakes and sloving a problem in LeetCode. And I will remind what should be paid more attention when doing search. ...