School of Hackers

This topic has 7 replies, 6 voices, and was last updated 21 years, 11 months ago by SphinX.

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November 19, 2004 at 1:38 am #14835

SphinX
Member

This is the first question on the Moscow school of hackers. I solved it in around 30 seconds.

You have integers x and y, you need to switch their values. You cannot use any other space in the memory except those two.

If you answer it, make sure to use the [ /spoiler] tags, and no syntax please.

November 19, 2004 at 1:45 am #105286

David
Participant

Took me 4mins. =)

November 19, 2004 at 7:24 am #105285

DJHyperbyte
Member

Took me about 30 seconds too…

[SPOILER]int x = 4, y = 5;

x = x + y;
y = x – y;
x = x – y;[/SPOILER][/CODE][CODE]int x = 4, y = 5;

x = x + y;
y = x – y;
x = x – y;[/CODE]

November 19, 2004 at 9:50 pm #105290

SphinX
Member

Your solution is right DJHyperbyte.
Dave is also correct.

Edit: Mistake

November 19, 2004 at 9:52 pm #105284

detn8r
Participant

I don’t get it – where is Dave’s answer?

November 19, 2004 at 9:54 pm #105287

David
Participant

Actually it works fine.

int x = 4, y = 5;

x = x + y;
y = x – y;
x = x – y;

November 19, 2004 at 10:00 pm #105289

Spike
Member

Took me 20-25 mins, but I got it.

There’s no point in putting the answer up, it’s already there. So just trust me 😉

November 21, 2004 at 12:43 am #105288

Crazy Penguin
Member

hmmmm…. that was easy enough, took me about a minute… though I was wierd and did it the opposite way to DJ and Dave :p

And i’m completely useless at compueter programming and stuff… however this is question 1 of the test… I expect I would be completely stuck on question 2, it looks like a standard easy starter question.

y= x + y
x= y – x
y= y – x
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