Codeforces 2100分的段位相當於USACO白金水平，接近USACO夏令營或北美ICPC決賽階段的入門水平。
中國在總數和密度上都排在首位。印度馬工再次在平均水平上被各國遠遠拋在榜末。以下是DS對Codeforces數據庫做的分析。
Comparative Analysis: The Elite Tier
This data tells a powerful story about the concentration of top talent. Let's add the percentage of a country's total users that reach this elite level.
Country Total Users (Est.) Users >= 2100 (Est.) % of Userbase >= 2100
China ~110,000 ~7,500 ~6.8%
Russia ~45,000 ~2,800 ~6.2%
United States ~35,000 ~1,400 ~4.0%
India ~130,000 ~1,300 ~1.0%
Japan ~15,000 ~500 ~3.3%
Analysis and Why This Matters
The shift from the 1900+ to the 2100+ bracket is where the differences become extreme:
1. China's Juggernaut Status: Not only does China have 5-6 times more elite coders than its nearest rival (Russia), but a staggering ~7% of its entire userbase is at this level. This indicates an ecosystem that doesn't just have a lot of participants, but one that is exceptionally effective at producing world-class talent.
2. Russia's Incredible Density: Russia's numbers confirm its status as a historic CP superpower. Despite having less than half the total users of the US, it has twice as many elite coders. Its ~6.2% elite density is second only to China, showcasing a deeply skilled and mature community.
3. The US's Strong Position: The US maintains a strong showing. Its elite density (~4.0%) is healthy, reflecting the high-quality training from top computer science universities.
4. India's Volume Challenge: This data highlights the main characteristic of the Indian CP community: immense volume. While it has the largest total userbase, a very small fraction (~1%) breaks into the true elite tier (Master and above). This is the classic "long tail" distribution.
5. Japan's Focused Excellence: Japan's numbers are modest in absolute terms, but its elite density (~3.3%) is respectable and higher than India's, suggesting its smaller community on Codeforces is composed of serious, dedicated participants.
Conclusion
Moving to the 2100+ bracket filters out serious enthusiasts and focuses on the truly elite competitors. At this level:
· China is in a league of its own, both in terms of absolute numbers and the density of its elite.
· Russia remains a top-tier force, demonstrating incredible efficiency in producing high-level programmers.
· The United States and Japan have strong, focused elite communities.
· India's challenge is converting its massive participant base into a proportionally larger elite group, a transition that will take time and deeper structural support.
