There are two winners of CEOI 2018. Mariusz Trela from Poland and Costin-Andrei Oncescu from Romania. They scored absolutely equal points – made 100% of 5 problems and their solutions passed exactly the same tests on the sixth problem FIB. Complete tie. By the way, both of them claim to have had a 100% algorithm in mind during the contest, and only lack of time for coding prevented them to score this result.
Their histories that led them to the current success, however, differ in many aspects. Mariusz comes from a big Polish town, Kraków, and attends the renowned high School, the best one in computer science in the whole region. From this school a number of finalists of Polish OI come every year. Last year Mariusz achieved a remarkable result winning individually two Polish olympiads: in informatics and in mathematics. He also scored two gold medals on two international olympiads: IMO and IOI. Mariusz school created a wide community of interacting students and excellent teachers, who support each other in various ways.
On the other hand, Costin comes from a relatively small town and attends local high school with no such community. Costin discovered his outstanding math and programming abilities and achieved this international level in programming more or less alone. He learned programming from tutorials and only his self-confidence combined with hard work lead him to this outstanding level. He reported me that in the past year he has solved about 600 programming tasks from various contest sources; Mariusz says that in his whole life he did not do that many.
I am impressed by the achievements of both of them.