ZIO 2016 Discussion

r4huln · November 17, 2015, 7:07pm

@xorfire Would be great if you also posted how to solve them(or some sort of hint) especially the first and second questions

geekpradd · November 17, 2015, 8:20pm

Can anybody provide an explanation for 2 A?

Is it 36 or 40?

Most people have got either 36 or 40 in this thread. Which one is correct?

homothety8 · November 17, 2015, 10:18pm

for first question just count the over countings. S=11011. if aSb=cSd then the string must have conjoined S’s. see the possibilities.
for the second, i counted the possibilities of 0 R, 2 R, 4 R, etc.

sanket1001 · November 18, 2015, 2:32pm

@ZIO2016:
quedtion 3 can be solved by exclusion and inclusion…any other method

anukul · November 18, 2015, 2:53pm

@sanket1001 Question 3 can be solved using recursion, the recurrence relation being F(n) = n! - \sum\limits_{i=1}^{n-1} i! \cdot F(n-i)

equinox · November 21, 2015, 5:33am

Guys the official keys are out! http://www.iarcs.org.in/inoi/2016/zio2016/zio2016-solutions.pdf

1 a. 75   b. 175    c. 399  
2 a. 40   b. 52     c. 96   
3 a. 71   b. 461    c. 3447 
4 a. 13   b. 10     c. 12

Getting 40… class 11. Hope that’s enough to make the cut.

shreyas_k · November 23, 2015, 3:16pm

This is my first time and I did quite bad… from what I remember of my answers I’m getting only last question fully right. Can anyone suggest efficient and logical ways of solving the other questions? Even if I arrive at an answer I’m not confident about it.

arpanbiswas97 · November 25, 2015, 10:25am

Hey does anyone know the cutoff for class 12 in this year’s ZIO? I am getting 40.

homothety8 · November 25, 2015, 5:06pm

When are the results supposed to come? The week’s almost over…

iambinit · November 25, 2015, 9:10pm

I think i wont get i solved the first and last problem perfectly
Wat is the cut off

mathecodician · September 15, 2016, 3:36pm

how was the answer 75 in the first question it should be 80.

dmhero · November 15, 2015, 7:14pm

n any idea abt when the result would be declared?

nibnalin · November 15, 2015, 7:40pm

Sweg level: ∞

shubham99 · November 15, 2015, 11:08pm

Can we have these problem sets for practice please in practice section of codechef? Please provide the link for aforesaid.

theweblover007 · November 16, 2015, 12:39pm

I think you must report this immidiately to madhavan sir’s email address.
It would be really sad to see the honest ones getting rejected and those retards getting selected and having no clue for INOI.

additya1998 · November 16, 2015, 4:25pm

Report it. ASAP.
Things were bad for ZCO participants too. Compiler wasn’t working, yes, that bad.

nibnalin · November 16, 2015, 9:49pm

Yes, these seem correct to me. I wrote a brute force yesterday, and that produced same results. So, unless we have common flaw in logic, it should be correct.

anukul · November 17, 2015, 3:42pm

what? `

xorfire · November 17, 2015, 8:38pm

Let X_i = set of all strings such that 11011 occurs at the ith position.

So, for example X_1 is the set of all strings starting with 11011.

Now, the answer is number of elements in (X_1) U (X_2) U …, use inclusion exclusion.

theweblover007 · November 17, 2015, 9:14pm

@additya1998 Had this problem at our centre too. @lelouch007 , Do report it.