GATE CSE
First time here? Checkout the FAQ!
x
0 votes
239 views
If the binary search algorithm determines that the scanned argument is in upper half of the array,which of the following statement will set the appropriate variable to the appropriate value.

A) startsub= middlesub-1;

B) startsub=middlesub+1;

C)stopsub=middlesub-1;

D)stopsub=middlesub+1;
asked in DS by (421 points)   | 239 views

2 Answers

+2 votes
Best answer
Option B is Ans

Cz as we know the Searching element is in Upper half then We will Increase the middlesub index  by 1. So that our search space is reduced by half.

So stopsub as it is and startsub=middlesub+1

So option B is correct Ans.
answered by Veteran (17.1k points)  
selected by
For the binary search ,the array is order(ascending).So if we know searching element is in upper half ,means that we should continue search in upper half.So our lower index would change and not the upperindex..

My confusion is with the understanding of the question.what the question mean when it says "Scanned argument".Is it the key that we want to search (search argument) or the scanned array element.

If search argument is less than the middle element the we do stopsub=middle -1;

And if the search argument is greater than middle element then we do startsub=middlesub+1;

Please solve my doubt around the question understanding.
Oh..Yes I have drawn the array vertically ;;So I Thought that Upper half means LHS..

But Now I drawn it horizontally..Cz max people do so.

&Ur Doubt:--It is the search element

 

See my Edited Ans..->>Thanks for Comment
+1 vote
B. startsub = middlesub + 1
answered by Loyal (3.5k points)  


Top Users Jul 2017
  1. Bikram

    5784 Points

  2. manu00x

    3602 Points

  3. Arjun

    1988 Points

  4. Debashish Deka

    1924 Points

  5. joshi_nitish

    1908 Points

  6. pawan kumarln

    1680 Points

  7. Tesla!

    1426 Points

  8. Hemant Parihar

    1334 Points

  9. Shubhanshu

    1180 Points

  10. Arnab Bhadra

    1124 Points


24,169 questions
31,187 answers
71,039 comments
29,512 users