viliml's blog

What is hacking?
By viliml, 12 years ago, In English

Hi! I'm new here, and I don't really understand hacks, what they are, how to hack, what to hack, who is the defender, what does he do, how to become one, etc. Simply said, I know nothing about hacks!

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12 years ago, # |
← Rev. 3   Vote: I like it +9 Vote: I do not like it

I'm new here

Welcome to codeforces :)

what they are

hacking is to give a testcase that makes a solution to a participant fail(i.e Wrong Answer,runtime error, time limit exceeded)

who is the defender

the owner of the code that you try to hack

what does he do

he do nothing ,if his solution is absolutely correct then no one can hack his code

how to hack

On the dashboard, click the padlock icon for locking a problem (Note, that you can not send your solution for a problem after locking it). Then go to room results, where you can see roommates codes for the problems you've already locked (you can see a certain solution by double clicking on it in the room results table). After you've opened someone's solution, you can consider it and then hack it. When hacking a code, you're entering some testcase on which that code is most likely going to fail (it may be wrong answer, or running out of time/memory limit). When you want to enter a large testcase, you can send test generator instead of typing it. Test generator must be your program which produces a file with a testcase in it. After hacking a code, you can see hacking results. There are two possible outcomes: "Successful hack" — it means the code failed, and you're rewarded with 100 points for that. Otherwise, it's "Unsuccessful hack" (the code did not fail) and you get minus 50 points for that.

quoted from jskhirtladze

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    12 years ago, # ^ |
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    Thank you very much for explaining!

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    9 years ago, # ^ |
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    what if i want to know the test case that hack my solution is there anyway i can check it?

    thank you however. your article is really clear.

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      9 years ago, # ^ |
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      You can check it after the contest is over Open the contest and choose Hacks tab

      Or simply check your submission from your profile

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    6 years ago, # ^ |
    ← Rev. 2   Vote: I like it -11 Vote: I do not like it

    Does the hacks during open hacking phase give the points too?

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12 years ago, # |
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It's penetrating into someone else's computer.

:/

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7 years ago, # |
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if i do not lock my code , than it is not hackable . am i right ??? or is it hackable ?? ( i am beginner )

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    7 years ago, # ^ |
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    If you dont lock your code than you cant hack other solutions, but your solution can be hacked by other participants.

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5 years ago, # |
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After viewing the test case on which my code was hacked,the test case showed same output when I tried it on one of the correct solutions.Are there any other possible reasons of a code getting hacked ?

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    5 years ago, # ^ |
    ← Rev. 2   Vote: I like it +1 Vote: I do not like it

    maybe your computer is working tooooooo well and it passed the data but it got a "time limit exceeded" on the judging computer of Codeforces. Just like the time limit is 1000ms, and your program ran for 950ms on your computer but failed on Codeforces' computer, maybe it ran for 1001ms on Codeforces :(

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    5 years ago, # ^ |
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    or maybe some unexpected Runtime Error or Memory Limit Exceed, etc.

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2 years ago, # |
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What kind of contest can be hacked? It seem like it include Educational round

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    2 years ago, # ^ |
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    Div.4, Div.3 and Educational rounds include 12-hours hacking stages after the end of the contest.

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