### Roms's blog

By Roms, history, 19 months ago,

1223A - CME

Idea: Roms

Tutorial
Solution (Roms)

1223B - Strings Equalization

Idea: Roms

Tutorial
Solution (Roms)

1223C - Save the Nature

Idea: MikeMirzayanov

Tutorial

1223D - Sequence Sorting

Idea: Roms

Tutorial
Solution (Roms)

1223E - Paint the Tree

Idea: Neon

Tutorial
Solution (Ne0n25)

1223F - Stack Exterminable Arrays

Idea: Roms

Tutorial
Solution (Roms)

1223G - Wooden Raft

Tutorial

1240F - Football

Idea: MikeMirzayanov

Tutorial
Solution (arsijo)

• +112

By Roms, history, 3 years ago, translation,

1030A - In Search of an Easy Problem

Tutorial
Solution

1030B - Vasya and Cornfield

Tutorial
Solution

1030C - Vasya and Golden Ticket

Tutorial
Solution

1030D - Vasya and Triangle

Tutorial
Solution

1030E - Vasya and Good Sequences

Tutorial
Solution

1030F - Putting Boxes Together

Tutorial
Fenwick Solution
Segment Tree Solution

1030G - Linear Congruential Generator

Tutorial
Dynamic Connectivity Solution
Greedy Solution

1053E - Euler tour

Tutorial
Solution

• +93

By Roms, history, 3 years ago,

1041A - Heist

Tutorial
Solution

1041B - Buying a TV Set

Tutorial
Solution

1041C - Coffee Break

Tutorial
Solution

1041D - Glider

Tutorial
Solution

1041E - Tree Reconstruction

Tutorial
Solution

1041F - Ray in the tube

Tutorial
Solution

• +148

By Roms, 3 years ago, translation,

Hello, community!

Codeforces Round #509 will be held on Sep/16/2018 13:35 (Moscow time). The round will be rated for Div. 2 contestants. There will be 6 problems for 2 hours. Please, notice that the start time is unusual.

The round will be rated for the div. 2 participants. The statements will be available in Russian and English languages.

The round will start 2 hours after the start of the Qualification Stage, so they will finish around same time. That's why we ask the participants of the Quals to stay silent and don't share the statements of the contest with anyone. Unfortunately, we cannot add all the problems from Quals to the round, it will contain only six problems.

The problems for the official contest were prepared by the guys from the jury in the person of Alex fcspartakm Frolov, Adilbek adedalic Dalabaev, Ivan BledDest Androsov and me.

We also would like to express our gratitude to Anton arsijo Tsypko for coordination of the round and Mike MikeMirzayanov Mirzayanov for the permission to make a mirror and Codeforces and Polygon platforms. Also big thanks to the testers: IlyaLos, Perforator, kuviman, HolkinPV, MaxZubec, stanislav.bezkorovainyi, Karasick for testing.

As usual, the scoring distribution will be announced just before the round.

Good luck!

UPD: Scoring Distribution: 500-1000-1500-2000-2500-3000

UPD2: Editorial