Codeforces Beta Round 39

Solutions for Codeforces Beta Round 39 (contest 40). 5/5 problems verified against sample I/O. Difficulty range: 1300-2600.

5 items

Codeforces Beta Round 39

Type: Beta | Problems: 5 | Verified: 5/5 | Rating range: 1300-2600 | Time: 7m 51s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Find Color	1300	constructive-algorithms, geometry, implementation	1m 24s	✓
B	Repaintings	1600	math	1m 44s	✓
C	Berland Square	2300	implementation, math	1m 38s	✓
D	Interesting Sequence	2600	math	1m 55s	✓
E	Number Table	2500	combinatorics	1m 10s	✓

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CF 40A - Find Color

The plane is colored using concentric rings centered at the origin. Every ring between two consecutive integer distances alternates color. The borders themselves, meaning all points whose distance from the origin is an integer, are always black.

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CF 40B - Repaintings

We start with an n × m chessboard. The top-left cell is black, so the coloring alternates exactly like a normal chessboard. Only the initially black cells participate in the repainting process.

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CF 40C - Berland Square

We have two families of circles on the infinite plane.

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CF 40D - Interesting Sequence

The sequence starts with two fixed values:

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CF 40E - Number Table

We are given a table representing the economy of Berland over n days and m months. Each cell in the table contains either 1 or -1, indicating a profit or a loss for that day of that month.