Hello Programmers!

I would like to invite you to participate in June Cook-off, it will start at Sunday, 26th June, 2016 at 21:30 HRS (IST), and will last for 2.5 hours, The contest will have 5 algorithmic problems of varying difficulties. the link to contest here.

**Problem Setter:**kingofnumbers (Hasan Jaddouh)**Problem Tester:**mgch (Misha Chorniy)**Editorialist:**pushkarmishra (Pushkar Mishra)**Mandarin Translator:**huzecong (Hu Zecong)**Russian Translator:**Antoniuk (Vasyl Antoniuk)**Vietnamese Translator:**VNOI Team**Contest Admin:**PraveenDhinwa (Praveen Dhinwa)

Top 10 international and top 10 Indians will get CodeChef laddu, find more about them here.

Feel free to discuss the problems after the contest, I hope you will find the problems interesting, looking forward to see you in the contest.

For CAKECUT is there any other solution in

O(N^{2}) or O(N^{2}log N) ? I know only of anO(N^{3}) algorithm.The intended solution is O(N^3) with bitset optimization (which make it N^3/32), you can read about the solution in the editorial

Actually when I came up with this problem I tried to solve it with a solution without bitset but after trying hard I couldn't find a better solution than bitset solution, so I decided to let it be the intended solution and hoping that someone will submit a solution during the contest of complexity O(N^2) or O(N^2 log N) without bitset, after the contest I looked at all correct submissions but all of them are the same solution with bitset.

I would be very happy if someone can find a solution without bitset and explain it to us.

In the editorial, shouldn't the formula for

count0 bec0·(c0 + 1) / 2 ? Because there might be a submatrix that has even sum and its left edge is the first column of matrix.Okay, the formula which I mentioned above is right but if you increment

c0 by 1, thenc0·(c0 - 1) / 2, can also be used(which is what editorialist has done), but I think it should be mentioned in editorial to not confuse others.I didn't understand from the editorial how is it that the amount of good rectangles increases by

c_{0}·(c_{0}- 1) / 2.Could you elaborate on that?

c0 is the count of zero's after XORing 2 rows. What does a 0 at placeiindicate? It indicates that submatrix between the 2 rows which were XORed, the left most column and the column at positioni, has an even sum. So how many even sum submatrices can we create which end in these 2 rows? We can choose any 2 out of all occurrences of 0s. Hence the formula. Note that you have to increasec0 by 1 to count submatrices which have column number 1 as the leftmost column.hi everyone! i saw one of the accepted solutions:- https://www.codechef.com/viewsolution/10621740 here h^4 and s^2 is directly used which will overflow in c++ according to constraints.. then why this gets accepted?? any thing i am missing out.. please help..

The data-type used for h and s is

`double`