Competing in programming contest of ACM is as tough as cracking International Maths Olympiad.
Russians/East Europeans(and some times West Europeans also

)are somewhat more mathematically inclined than others.
Thats why you can see , they can crack IMO/ACM contests compared to others.Many of 20th century Mathematicians,Computer Scientists were from East Europe/USSR.
In school(thats in 80s)we used to see many Math/phy books by russian authors in book fairs(specially by Mir Publishers).Majority of the books used to be loaded with supertough problems

Even books having similar title like 'Introduction to (Name of Subject)'used to contain problems from Page 1

and these books were supposed to be for 7th/8th grade students, when we used to read in 10 th grade.
After 1991, Mir Publishers was closed down and everything stopped.
Any Russian friend knows whereabout Mir Publishers??
About Jew Indians:Shura,Indian jews I have seen were of 2 catagories(This is not the generalization but my observation

).Either they are very brilliant or -----.In my school they were 2, brother/sister.Brother was the real genius,used to read the books 2 grades ahead.