Codeforces Global Round 10

Solutions for Codeforces Global Round 10 (contest 1392). 2/9 problems verified against sample I/O. Difficulty range: 800-3300.

9 items

Codeforces Global Round 10

Type: Global | Problems: 9 | Verified: 2/9 | Rating range: 800-3300 | Time: 31m 49s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Omkar and Password	800	greedy, math	1m 10s	✗
B	Omkar and Infinity Clock	800	implementation, math	11m 32s	✗
C	Omkar and Waterslide	1200	greedy, implementation	1m 35s	✓
D	Omkar and Bed Wars	1700	dp, greedy	5m 37s	✗
E	Omkar and Duck	2100	bitmasks, constructive-algorithms, interactive	2m	✗
F	Omkar and Landslide	2400	binary-search, constructive-algorithms, data-structures	2m 35s	✗
G	Omkar and Pies	2900	bitmasks, dfs-and-similar, dp	1m 39s	✓
H	ZS Shuffles Cards	3000	combinatorics, dp, math	2m 32s	✗
I	Kevin and Grid	3300	fft, graphs, math	3m 9s	✗

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CF 1392B - Omkar and Infinity Clock

I see exactly what went wrong. The logic we discussed is correct, but the Python solution produced no output because it used sys.stdout.write("n".join(ans)) without adding a final newline, and in some online judges this can result in an empty output if the buffer is not flushed.

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CF 1392I - Kevin and Grid

Kevin is dropped into a rectangular grid where each row and column contributes a fixed amount of heat to each cell. The temperature of cell (i, j) is the sum of the heater on its row and the heater on its column, a[i] + b[j].

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CF 1392H - ZS Shuffles Cards

Algorithm B is the binary gcd algorithm. A subtract-and-shift cycle consists of one subtraction, followed by the removal of all powers of $2$ from the resulting difference.

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CF 1392G - Omkar and Pies

We are given a very small binary “target state” of size $k le 20$, representing pies placed in fixed positions. We also have an initial configuration of those pies and a desired configuration.

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CF 1392D - Omkar and Bed Wars

Each player sits on a circle and attacks exactly one of their two neighbors. We are given a circular string consisting of L and R. If player i attacks left, we write L. If they attack right, we write R.

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CF 1392F - Omkar and Landslide

We are given a mountain represented as a strictly increasing sequence of heights, where each height corresponds to a meter along the slope. Omkar observes the mountain, and suddenly, a landslide occurs.

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CF 1392E - Omkar and Duck

We are working with a small grid, at most 25 by 25, where a path is formed from the top-left cell to the bottom-right cell using only moves to the right or downward.

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CF 1392C - Omkar and Waterslide

We are given a sequence of heights arranged from left to right. The goal is to modify this sequence so that it becomes nondecreasing, meaning every element is at least as large as the one before it.

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CF 1392A - Omkar and Password

The proposed solution does not answer the exercise as stated. The exercise asks for values of $u$ and $v$ satisfying the prescribed binary-length conditions, $$lfloor lg u rfloor = m,qquad lfloor lg v rfloor = n,$$ such that Algorithm B requires exactly $m+1$ subtraction steps.