Binary Search Help

[Justin Meyer]

 

So I was hoping someone could help me figure out some question that i have about some binary searching in my java script class that im in. So in the picture it gives you an array with some specific numbers in it and it asks what the indexes examined and the value returned would be. So i know how to get the values returned however the indexes examined is still confusing and i dont know how to get the answer. Could someone explain how to get that answer and why.

[fizzlesticks]

Every time you pick a new midpoint in your search algorithm just print it.

[Justin Meyer]

 

 

Every time you pick a new midpoint in your search algorithm just print it.

Wait this was a different problem than i thought. I dont know how to get the value returned on this one because there is no 86 assigned to an index.

[Imabigmac]

 

 

 

Wait this was a different problem than i thought. I dont know how to get the value returned on this one because there is no 86 assigned to an index.

 

Then it will search anyway, but it will never find 86. 

[Justin Meyer]

Then it will search anyway, but it will never find 86. 

So then what would the answers be if it cant find the values?

[fizzlesticks]

So then what would the answers be if it cant find the values?

We don't have the algorithm you went over in lecture, we don't know.

[Justin Meyer]

 

 

We don't have the algorithm you went over in lecture, we don't know.

 

Wtf she never gave us an algorithm

[Imabigmac]

Wtf she never gave us an algorithm

 

then it is not solvable... With those numbers you will never get a index value for "86", but you will likely get outputs for "Indexes examined" up to 13 - but that will depend on what the algorithm is exactly. Algorithm may compare 86 to 89 and stop because you have gone too far. 

[madknight3]

Wtf she never gave us an algorithm

 

Are you sure? The questions states "Assume that we are using the binary search algorithm shown in lecture and section." so there should be something. Maybe you missed it or simply don't remember it being shown to you. Reviewing your notes/textbook or asking someone in your class might help. If that fails to resolve the matter then talk to your teacher.

 

It's also possible that it's hasn't been covered in class yet and will be covered before the assignments due date. I've had this happen in classes before although I wouldn't take a chance.

[LordXenu]

Found where this came from

 

http://practiceit.cs.washington.edu/problem.jsp?category=University+of+Washington+CSE+143%2FCS2+Exams%2FCS2+Final+Exams%2F143+Practice+Final+2&problem=143practicefinal2-binarySearch