Educational Codeforces Round 93 (Rated for Div. 2)

Solutions for Educational Codeforces Round 93 (Rated for Div. 2) (contest 1398). 2/7 problems verified against sample I/O. Difficulty range: 800-2600.

7 items

Educational Codeforces Round 93 (Rated for Div. 2)

Type: Div. 2 | Problems: 7 | Verified: 2/7 | Rating range: 800-2600 | Time: 27m 27s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Bad Triangle	800	geometry, math	11m 19s	✗
B	Substring Removal Game	800	games, greedy, sortings	1m 18s	✓
C	Good Subarrays	1600	data-structures, dp, math	7m 51s	✗
D	Colored Rectangles	1800	dp, greedy, sortings	1m 23s	✓
E	Two Types of Spells	2200	binary-search, data-structures, greedy	1m 52s	✗
F	Controversial Rounds	2500	binary-search, data-structures, dp	1m 44s	✗
G	Running Competition	2600	bitmasks, fft, math	2m	✗

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CF 1398A - Bad Triangle

This failure is not caused by the algorithm at all. It is a pure syntax error in the test harness. The traceback says: So the string passed into run() is never closed.

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CF 1398G - Running Competition

We are asked to model a running stadium as a rectangle subdivided by vertical lines. The horizontal sides run from (0,0) to (x,0) and (0,y) to (x,y), and there are n+1 vertical segments at coordinates a0, a1, ..., an, which connect the top and bottom edges.

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CF 1398C - Good Subarrays

Ah! Now the problem is crystal clear. The error: tells us exactly what’s wrong: your code is assuming that every line after the header has 3 integers (u v w), but the actual input is inconsistent: - Some lines have 3 numbers (edges with weight: 1 3 100) - Some lines have only…

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CF 1398F - Controversial Rounds

We are given a long sequence of match outcomes, where each position is either a win for Alice, a win for Bob, or unknown. The actual game is not just a flat sequence of independent results.

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CF 1398E - Two Types of Spells

Each update in this problem either adds or removes a spell from Polycarp’s arsenal. Every spell belongs to one of two classes. A fire spell contributes its raw value as damage when cast.

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CF 1398D - Colored Rectangles

We are given three collections of sticks, grouped by color. Every color group contains several stick pairs, and each pair has a single length value.

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CF 1398B - Substring Removal Game

The game operates on a binary string that can be thought of as a sequence of adjacent blocks of identical characters. On each turn, a player removes a contiguous segment consisting of equal characters, and the two remaining parts of the string are stitched together.