### MikeMirzayanov's blog

By MikeMirzayanov, 4 months ago, You can view PDF version of the tutorial by the link.

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Tutorial is loading...  icpc, nerc, 2020, Comments (25)
 » That trick for pairs in problem M is just awesome... During the whole contest we were struggling to remove that logn factor but couldn't find the way.
•  » » https://codeforces.com/contest/1468/submission/102338964 Can you tell why this is giving runtime error in test 46 I am not able to figure it out..
 » 4 months ago, # | ← Rev. 2 →   Nice editorial
 » Thanks for this Tutorials, It was a very cool contest, But there were a lot of test cases, which caused the long queue.
 » 4 months ago, # | ← Rev. 2 →   I think that there is a mis-written part in problem A in editorial: a[posi−1]≤a[posi]≥a[posi+1] should be a[posi−1]≤a[posi]≤a[posi+1]
•  » » i can not understand editorial for A. can you explain?
 » I think there is an error in tutorial for L. "If there are no more than 2 such integers" (second sequence) should be "If there are no more than 1 such integers" or "If there are less than 2 such integers". Because in next paragraph $k_i > 1$ implies that $p$ can be important if there are 2 numbers of form $p^q$.
•  » » Yes, you are correct. Thank you!
 » MikeMirzayanov is there an alternate to these explanations , it is difficult for me to understand this editorial.
 » Please someone can explain similar sets(problem M) editorial.
 » 4 months ago, # | ← Rev. 5 →   Thanks for good problems
 » for problem c, i just used two different sets, one for each operation type, sorting elements as either (i, m) or (m, i), where m is the estimated money and i is the customer number. this makes finding which customer is served much easier, as you can take from the front of the first set for the 1st operation and from the back of the second set for the 2nd operation
 » 4 months ago, # | ← Rev. 2 →   For M, how is finding all pairs (x,y) not time complexity (k^2)? How exactly do you create a separate array for each integer x and then add all values y to it
 » For L, I'm getting wrong answer on test case 99 (because I'm only able to find a sequence of 994 items, not 1000). Is this happening to anyone else?
 » 4 months ago, # | ← Rev. 2 →   In problem C Berpizza why I am getting tle on test case 12 My code please let me know and also how to resolve it
•  » » I notice that you are sorting the vector every time a monocarp or polycarp query is done. This is probably making it slow. You can instead try using sets as they are implemented using binary-search trees and will be faster (O(log n) vs O(n logn) per query). My submission using sets
•  » » » Thanx. Now it was all clear to me
 » In problem M's tutorial, does it mean that: For every small sets, we find all pairs, which is O(k^2) where the k is the size of the sets. There are M/k sets so that their are O(M*k) pairs in total? How should I implement it? I tried 2 dimension unorderedmap but TLE.
 » Can anybody share the code of C. Berpizza
•  » » See in my submissions
•  » » #include using namespace std; typedef long long int ll; typedef vector vi; typedef vector> vvi; typedef vector vb; typedef pair pii; #define fo(i,s,e_ex) for(i=s;i=n;kb.second; } return a.first, decltype(&compForPair)> poly(compForPair); priority_queue > mono; cin>>q; while(q--){ cin>>type; if(type==1){ cin>>m; poly.push(mpp(m,guestNo)); mono.push(guestNo); guestNo++; }else if(type==2){ while(true){ ll gtorem = mono.top();mono.pop(); if(guest[gtorem]==1){ cout<>t; for(ll i=1;i<=t;i++){ solve(i); } return 0; } 
 » 3 months ago, # | ← Rev. 2 →   In problem C, can anyone tell me why my code is failing in the seventh test case that too by swap of two digits(136 in place of 133 and 133 in place of 136)? source: 105199970Approach: I have used two priority queues with pairs to store customer id and price sorted with respect to id in ascending order for monocarps queries and sorted with respect to price in descending order for polycarps queries. And I have used unordered_map to check which id's have already been served.
 » My code for question c is giving tle on test case 17 plz help!!!!!
 » Can someone help me with problem K. I am not able to figure out where I am doing mistake? Your code here... #include using namespace std; #define ull unsigned long long #define ll long long #define f first #define S second #define mod 1000000007 int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(0); // freopen("input.in", "r", stdin); // freopen("output.in", "w", stdout); int t; cin>>t; while(t--) { string s; cin>>s; int c = 0; for(int i=0;i>left(s.length()+1); vector>ryt(s.length()+1); for(int i=0;i=0;i--) { ryt[i] = ryt[i+1]; if(s[i]=='L') ryt[i].f-=1; else if(s[i]=='R') ryt[i].f+=1; else if(s[i]=='U') ryt[i].S+=1; else if(s[i]=='D') ryt[i].S-=1; } vectorinx(s.length()); for(int i=0;ii) inx[i] = inx[i-1]; else { int j = i+1; while(j < s.length() && s[i]==s[j]) j++; inx[i] = j; } } } int b = 0; inx[s.length()-1] = s.length(); for(int i=0;i
 » "Now, we can note that each a[i] is either minimum in LaIS or i = nxt[j] for some other element a[j]".Can someone give me a proof of that?