Even last years ZCO problems seemed harder than last years INOI problems XD
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@ista2000 Are you sure it is top 200 or are you just pulling out random numbers. If thats the case even people with 10 points would get selected as only ~150 people had even scored any points, looking at the stats on the contest page.
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I think last yearâs ZCO was way harder.
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Yeah, I agree. The questions were harder than previous yearâs question.
So, the test started at 10:10 and ended at 13:10. So, I got 3 hours for the questions. But, many studentsâ computersâ timer went on for extra 10 minutes or so. When we told the invigilators, they told us to refresh our pages and try again, but nothing happened. The invigilators said they canât do anything about it.(I agree; it wasnât their fault).
I am not saying I got less time than the official time, but some people got more time which disadvantaged the rest of us as even 10 minutes in these contests mean a lot.
I request you to kindly look into the matter.
Hoping for a favourable response!
Yeah same, and I think it would have given AC because when I submitted my code it was giving WA, but all my answers were basically 1 less, but I ran out of time lmao RIP
nope. thg, @ista200 used sliding window
I asked arjun arul the intended solution. He told me it was similar to mine. thg, it was a bit different prefix sum
@taksh001 the timer showed extra 10 min but if u reloaded it or went to submission page it showed u re denied access the content so I feel no one got extra time only the timer was wrong that to if u have not reloaded the page.
Yes, three different prefix sums for each mod and then a sliding window algorithm.
Anyway, nice.
For the first one,
created a vector called dp with two integer elements. the first integer contained the importance of the substring till the current character(the current character being the last character of the substring of the intended length). The second integer contained the index of the closest previous âXâ character. Now I iterated through the string. If a[i] was z, I checked its length until previous Xs; if it was divisible by 3, I increased all the dp[i]s in the range of the checked Xs and the current z by 1. I kept checking that no Xs are repeated using a 2d visited array. If a[i] was X, I included it in dp index and updated dp[i] as dp[i-1]-1, checking it to be >0. Same if a[i] was Y, except that there was no updation in dp index.
Answer was minimum of all dp importances.
The questions were a lot harder than previous year, I focused everything on DP and boom the pattern changed.
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@monsterguy Same condition hereâŚsurprised @ the sudden change in pattern. Any noob would have told by looking at previous years questions that DP was a sureshot.
I donât think so. I was harder than zco questions <= 2016 but was way easier than inoi or zco 2017
I gave at IIITD center⌠The solution of second program was working perfectly on IDE but when I submitted it was showing NZEC error⌠What is the reason for it to be shown?
i used lower bounds and prefix sums
It doesnât matter now. I will try 100x harder next year.
The timer was extending only for the students who lost time due to system issues during the exam. For all the rest of the students the exam was end at 1:10 pm.