You can easily discover the simillarities between those competitor's code. Actually, It's more hard to find the difference.
- Struct names are different — one has "xvalue", other has "dat". but operator definition / initializators are all same.
- Function names are different — one has "doit", other has "foo". but, inside the function, everything is same — even the indentations / spaces are same, too!
- Several brackets / indentations are different in main function, but others are identical.
Another interesting thing is the submission from RNS_jgm one minute before AC — http://codeforces.com/contest/653/submission/16814808 This code is very different from the AC code. Then, how are these changes made in such a short time?
In usual competition, I don't go deeper to other's codes. But, when I discovered that my rating was right before IGM (2599), and reminded how I got red from 2199, I was really tempted to write this post! MikeMirzayanov, can you investigate into those issues?