Could you cite where it states that you have to be a US citizen? I can't see any restriction apart from the usual ones on Quebec and the axis-of-evil countries.
It's entirely possible that I'm looking at the wrong place, that's why I'm asking.
From the official rules and regulations:
"A Competitor is not eligible for this Competition if he/she is a resident of the Quebec province of Canada, [...]"
You don't have to be in the US: "(iv) a non-U.S. resident authorized in the country in which the member resides while participating in this Competition to perform services as an independent contractor."
And for those asking, I read through the terms and conditions until I bounced into this and jumped to a hasty conclusion...
Eligibility
This Competition is open to all members of the TopCoder website, who have agreed to the terms thereof, and who are at least 18 years of age. Competitors must be:
(i) a U.S. citizen,
(ii) a lawful permanent resident of the U.S.,
(iii) a temporary resident, asylee, refugee of the U.S., or have a lawfully issued work authorization card permitting unrestricted employment in the U.S., or
For the last line indeed says:
(iv) a non-U.S. resident authorized in the country in which the member resides while participating in this Competition to perform services as an independent contractor.