# Codeforces

Awesome list for CP: https://codeforces.com/blog/entry/23054 Lesson: Stop overestimating yourself.

How is the elo of a problem calculated?

Problem rating of x is supposed to mean that about 50% of coders rated x can solve that problem, about 75% coders rated x+200 can solve, or about 90% rated x+400 can solve the problem. > https://codeforces.com/blog/entry/62865

So if I want to reach 2000, I should be able to solve 2000 problems ~50% of the time.

Goal: Keep upsolving C and D. Itâ€™s going to be very difficult, but you really need to continue practicing and upsolving these problems. There is no point in just doing A and B problems, unless you really are using them to practice speed.

I need to do those contest simulations, but rather than doing the virtual simulation, just time yourself. Alternatively, binary search but thatâ€™s too easy. Problems I need to do:

- https://codeforces.com/contest/1567/problem/C (1600 problem)
- https://codeforces.com/contest/1405/problem/C (1500 problem)
- https://codeforces.com/contest/305/problem/B (continued fractions)
- https://codeforces.com/contest/356/problem/A (union find)
- https://codeforces.com/problemset/problem/1705/D
- Started implementing, but my brain isnâ€™t working: https://codeforces.com/problemset/problem/1553/D
- https://codeforces.com/contest/271/problem/D (string hashing)
- https://codeforces.com/contest/1527/problem/C
- https://codeforces.com/problemset/problem/1620/E (harder union find)
- https://codeforces.com/contest/1543/problem/C
- https://codeforces.com/contest/1543/problem/D2
- https://codeforces.com/contest/1537/problem/E2 (need string hashing)
- https://codeforces.com/problemset/problem/1621/B

Problems I have thought about but donâ€™t know:

- https://codeforces.com/contest/1604/problem/D (modular arithmetic, 1500)
- https://codeforces.com/problemset/problem/1554/B

Hard Problems I read editorial but still donâ€™t know:

To try again later:

**Solved but itâ€™s iffyâ€¦, like I donâ€™t understand:**

- https://codeforces.com/problemset/problem/1542/C
- https://codeforces.com/problemset/problem/1554/C https://c2-ladders.com/

Such an amazing platform. Some Blogs https://codeforces.com/blog/entry/48417

## Highest Tags Per Problem

https://codeforces.com/blog/entry/74822 Focus on DP if you want to solve D and E!!

- A â€”Â
**implementation**: 426,Â**math**: 176,Â**brute force**: 145 - B â€”Â
**implementation**: 321,Â**greedy**: 180,Â**math**: 171 - C â€”Â
**greedy**: 141,Â**implementation**: 137,Â**math**: 107 - D â€”Â
**dp**: 130,Â**greedy**: 103,Â**math**: 99 - E â€”Â
**dp**: 147,Â**data structures**: 122,Â**math**: 80 - F â€”Â
**dp**: 85,Â**data structures**: 55,Â**graphs**: 38 - G â€”Â
**data structures**: 28,Â**dp**: 20,Â**math**: 18 - H â€”Â
**data structures**: 4,Â**trees**: 4,Â**constructive algorithms**: 3