Thanks @vijju123
It seems surprisingly fine to me. Can you code the same and submit in C++? To rule out any language difference in this.
Yeah, but long is necessary only when I add more than 3 coordinates as Each coordinate is <10^9 which comes inside int. So it is sufficient to put Long long for temp1, temp2
Basically, I segregated the corrdinates into 9 types depending on the values mod 3,sk that I can guarantee that the triangle formed by three points will have its centroid as a lattice point. So I used pos[x%3][y%3]=make_pair(x,y).and iterated through the vector and found the centroid.
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@shubhu1596 I know this solution should not get AC but see that user is using midpoint formula of the line segment.Because there are n/2 lines, he could get n/10 points easily!
Well, My approach was to use O(N^3) brute force algorithm, coupled with a few observations, one being the same as official editorial. (Regarding Number of divisors)
Iāll try to post if i can, but no promise.
PS: Sorry for late reply
Yes, I even had more WAs on this problem alone than all other problems combined for this contest.
Only last day i used Modular Inverse that did the trick.
Maybe the excessive use of mod in block where t%2 != 1.
Canāt be sure because Iām not versed in python.
Yes, it can be labelled as easy-medium, If you get the obersvation.
One of my friend, rather better at coding than I am, didnāt even attempt this problem but solved all others (Partial in lucas, rest all 100). Only reason: He didnāt get these observations (due to geometry).
Thatās why i labelled it medium problem.
See the hidden part in editorial and read about modular multiplicative inverse.
Well, I had so many WAs in POINTPOLY trying to get the 30 point subtask- so many that I was afraid I will cross the 500 submission limit XD
For POINPOLY, i got 100 points in one go.
Frankly, i try to make as less submissions as possible. Otherwise, in longs of 2017, many problems had near 50 submissions of mine, with really minor differences (never reached 100 i guess).
Itās too an achievement, achieved by only a few 
@cis_pie what about those cases in which the mid point of such chords are same, the code does not even checks for such duplicate points
Soā¦looks like I am the only one who made 0 observations and crashed the party with rand() XDDDD I solved this Q only because rand() got me 70 points :3
There might be other users too, still in shadows, remaining masked unlike you.
remaining masked unlike you
Ironically, in real life I prefer remaining masked. I just dont like any kind of spotlight lol.
It's too an achievement, achieved by only a few ;)
Trueā¦but I still wont prefer it in Cook-offs 
:3
Probably that N=10 case was the trump card and should have been included for 70 pts case also as a lot of random techniques passed for 70 pts.