Questions tagged [binary-search]

Questions about the binary search algorithm, which can be used to find elements of an ordered list in O(log n) time.

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36
votes
2answers
14k views

Why is the log in the big-O of binary search not base 2?

I am new to understanding computer science algorithms. I understand the process of the binary search, but I am having a slight misunderstanding with its efficiency. In a size of $s = 2^n$ elements, ...
56
votes
3answers
27k views

Why is binary search faster than ternary search?

Searching an array of $N$ elements using binary search takes, in the worst case $\log_2 N$ iterations because, at each step we trim half of our search space. If, instead, we used 'ternary search', we'...
14
votes
3answers
3k views

Can this algorithm still be considered a Binary Search algorithm?

While doing the second code kata (which asks you to implement a binary search algorithm five times, each time with a different method), I've come up with a slightly different solution which works as ...
14
votes
3answers
748 views

Is there any study or theory behind combining binary search and interpolation search?

I just read Can this algorithm still be considered a Binary Search algorithm? and recalled that a few years back I wrote an indexer/search for log files to find log entries in large plain text files ...
2
votes
1answer
445 views

Searching a sorted array to find the $k$ closest values to a target value $T$

Let $A$ be a sorted array of $N$ values. I am interested in finding the index $j$ such that the elements $A_j, A_{j + 1}, ..., A_{j + k - 1}$ have the $k$ closest values to the given target value $T$. ...
1
vote
3answers
99 views

Dividing 2 integers with some constraints

This a problem i came across while practicing binary search. Here is the problem: Given two integers dividend and divisor, divide two integers without using multiplication, division and mod operator. ...
4
votes
3answers
2k views

Categorization of Binary search as Divide and Conquer

Why do we call binary search as 'Divide' and 'Conquer' strategy? It does not combine the results unlike other Divide and Conquer strategies.
1
vote
1answer
3k views

How to analyze/test a binary search algorithm?

I was asked to "Compute the average runtime for a binary search, ordered array, and the key is in the array." I'm not quite sure how to approach this problem. Isn't the runtime of binary search O(log ...