The Ethical Hacker Network - Any got a solution for this programming challenge ?

manoj9372

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Any got a solution for this programming challenge ?

« on: January 22, 2013, 09:57:35 AM »

hi guys,
here is challenge i got from my friend,i just want to know there is a solution available for this task,

when i enter a number it should display it's equivalent binary number like for 2 = 0010 3=0011,
but the important restriction is "IT SHOULD NOT USE/INVOKE MULTIPLICATION OR DIVISION OF ANY FORM" inside the computer.

is there a solution possible ?

if any one has one please post here...


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Dark_Knight

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Re: Any got a solution for this programming challenge ?

« Reply #1 on: January 22, 2013, 10:33:16 AM »

Yes..we won't do your homewrok for you Grin

.....just messing with you...


« Last Edit: January 22, 2013, 10:34:54 AM by Dark_Knight »	Logged

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hayabusa

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Re: Any got a solution for this programming challenge ?

« Reply #2 on: January 22, 2013, 10:41:34 AM »

Depends on the language... It's simple in python...

As of version 2.3

bin(x)
Convert an integer number to a binary string. The result is a valid Python expression. If x is not a Python int object, it has to define an __index__() method that returns an integer.

You'd just need to strip off the first two characters of the return, such as:

Code:

val=bin(8);
newval=val.replace("0b", "");
print newval;

Now, we'll assume that the bin() uses multiplication / division inside of itself, so if you really wanted to do this, without ANY, you'd likely need to create an array of values, during runtime, where you GIVE it the values, and parse the array to return them. That's if he's TRULY not allowing the use of the builtin functions of python to do the work...


« Last Edit: January 22, 2013, 10:45:18 AM by hayabusa »	Logged

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unicityd

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Re: Any got a solution for this programming challenge ?

« Reply #3 on: January 22, 2013, 10:46:05 AM »

Quote from: hayabusa on January 22, 2013, 10:41:34 AM

Depends on the language... It's simple in python...

As of version 2.3

bin(x)

I think the point of the challenge is to do it manually. The easiest way I can think of off-hand is to use a logical AND to test if each bit is set.


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H1t M0nk3y

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Re: Any got a solution for this programming challenge ?

« Reply #4 on: January 22, 2013, 11:13:10 AM »

Quote

"IT SHOULD NOT USE/INVOKE MULTIPLICATION OR DIVISION OF ANY FORM" inside the computer.

The important part is "inside the computer". In python, the bin() function might use multiplications and/or divisions.

You can always have a whole bunch of "if" statements. That's not elegant, but it would work for sure:

Code:

int number;

//Set the value of the "number" variable somehow

if(number == 0){
   return "0000";
}
else if(number == 1){
   return "0001";
}
else if(number == 2){
   return "0010";
}
...

You can also fake multiplications with for loops:

Code:

int number1;
int number2;
int result = 0;

//Set the value of the "number1" and "number2" here

for(int i=0; i<number1; i++){

result = result + number2;
}

return result;


« Last Edit: January 22, 2013, 11:19:39 AM by H1t M0nk3y »	Logged

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hayabusa

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Re: Any got a solution for this programming challenge ?

« Reply #5 on: January 22, 2013, 11:19:00 AM »

I think unicityd's method is likely what they want.

@H1tM0nk3y... That's why I put my extra 2 bits in, at the end, and noted adding values in the array. You could simply create an array with all the values in order, then call from the positions, etc.

But really, I think unicityd's method is what they probably wanted. Wink


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manoj9372

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Re: Any got a solution for this programming challenge ?

« Reply #6 on: January 24, 2013, 02:20:50 AM »

To the first guy
i am not a school kid Grin

we need this logic to show that in REAL LIFE that program can produce much faster results than the hardware,that is the main task of this program and TBH i am not a programmer Huh

And guys when i asked for solutions for this program from other programmers they urged me to use some kind of bit shifting to do this,
and it seems "unicityd" points were right... Grin


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H1t M0nk3y

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Re: Any got a solution for this programming challenge ?

« Reply #7 on: January 24, 2013, 06:42:49 AM »

Ok, ok, I agree, unicityd has a better solution than me... Cheesy

I have way too many things on my plate right now to spend cycles on this.

Being a developer, I believe that CPUs and RAM are way cheaper than developer's time (at least, most of the time).

Good luck and please post your solution!


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