techInterview Discussion

try in any way you want

*yawn* paging Gene...

Here I am, d.  Having graduated earlier this month with a minor in Math, I swiftly despatch the nasty dragon^Wmath problem.

4 * (4 + 4 / 4)

All better?

Sincerely,

Gene Wirchenko
techInterview Moderator (and very small dragon killer)

I was thinking delete button but whatever.

I know, d.  A problem like this is actually much better than many of those posted here.  If I were to ask it though, I would want to know how someone would go about solving such a problem.  That would be more valuable to me than knowing that the candidate could solve the particular problem.

Sincerely,

Gene Wirchenko

The way I would approach a qustion would be to factor the required number,i.e., 20=2*2*5 or 4*5(Divide & Conquer)
So now the problem is divided in to 2 parts (4 & 5)

Now I have a 4, so now I am required to generate a 5 using three 4's. I try to generate a 5 by dividing it again into 4+1 since we have a 4 with us. The problem now comes down to generating a 1 using two 4's which can be done by 4/4, and now the problem is solved.
I could solve the problem in abt 5 min's, but there are many many more such number puzzles which are very diffcult to solve and require other complex operations like root, power, etc. So would you use the same procedure of divide & conquer or is there some other better way to approach such problems??

if few more mathematical operators allowed then ...

1. (44 - 4)/sqrt(4)
2. (4!) - 4 - 4 + 4
3. (4 + 4 + sqrt(4) ) * (sqrt(4))
4. (sqrt(4)^sqrt(4)^sqrt(4)) + 4
.
.

visit http://www.cracktheinterview.org/ for good collection of interview questions