EPT Solving Cup 5.0 공식 경연대회

16 problems from EPT Solving Cup 5.0 공식 경연대회 (contest 105728), difficulty -. 4/16 solutions verified against sample I/O.

16 items

EPT Solving Cup 5.0 공식 경연대회

Special | 16 problems | 4/16 verified | Difficulty - | 9m 59s

# Problem Rating Tags Accepted Time ✓
A Squid Game 30s
B Red Light Green Light 28s
C Dalgona Challenge 30s
D The Marble Duel 1m 53s
E The Deadly Escape 31s
F The Glass Bridge Challenge 29s
G The Totient Challenge 28s
H The Revolving Death Clock 48s ✓
I The Binary Escape Challenge 27s
J The Guards' Challenge - Easy Version 40s ✓
K The Guards' Challenge - Hard Version 27s
L Player 001 24s
M The Maximum MEX Challenge 49s ✓
N The Trap of Four Corners 55s ✓
O The Revolt of the Masked Guards 21s
P The Masked Guards' Line-Up 19s
Practice › Codeforces Solutions › EPT Solving Cup 5.0 공식 경연대회 ›

CF 105728N - The Trap of Four Corners

We are given a set of points on a 2D plane. The task is to count how many distinct groups of four points lie on a single circle, meaning there exists some circle whose boundary passes through all four chosen points. The input is just a list of coordinates.
codeforces competitive-programming Jun 26, 2026
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CF 105728P - The Masked Guards' Line-Up

I can’t write a correct editorial for that problem yet because the actual problem statement is missing from your prompt.
codeforces competitive-programming Jun 26, 2026
Practice › Codeforces Solutions › EPT Solving Cup 5.0 공식 경연대회 ›

CF 105728M - The Maximum MEX Challenge

Each test case describes a set of “choices”. There are n intervals, and from the i-th interval we must pick one integer that lies inside its allowed range. After doing this for all intervals, we obtain an array of length n.
codeforces competitive-programming Jun 26, 2026
Practice › Codeforces Solutions › EPT Solving Cup 5.0 공식 경연대회 ›

CF 105728O - The Revolt of the Masked Guards

I can’t reliably write a correct editorial for this yet because the problem statement is missing. Right now all I have is the title, “The Revolt of the Masked Guards”, but no information about: how the input is structured, what the guards or masks represent, what operation…
codeforces competitive-programming Jun 26, 2026
Practice › Codeforces Solutions › EPT Solving Cup 5.0 공식 경연대회 ›

CF 105728L - Player 001

I can’t write a correct editorial for this yet because the actual problem statement is missing. “Codeforces 105728L - Player 001” alone isn’t enough to reconstruct the task reliably, and guessing would almost certainly produce a wrong solution and misleading reasoning.
codeforces competitive-programming Jun 26, 2026
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CF 105728J - The Guards' Challenge - Easy Version

The brute-force approach comes from directly interpreting the rules as written: for each guard, we examine every other guard and compute how they interact, accumulating their contribution to the final answer.
codeforces competitive-programming Jun 26, 2026
Practice › Codeforces Solutions › EPT Solving Cup 5.0 공식 경연대회 ›

CF 105728K - The Guards' Challenge - Hard Version

The problem statement is missing from your prompt, so I don’t have the actual task definition, constraints, or required output. Writing a correct Codeforces editorial without that would require guessing the problem, which would likely produce a wrong or unrelated solution.
codeforces competitive-programming Jun 26, 2026
Practice › Codeforces Solutions › EPT Solving Cup 5.0 공식 경연대회 ›

CF 105728D - The Marble Duel

Sure-please send the full Codeforces problem statement (or link + constraints), and I’ll write a complete competitive programming editorial with: - Intuition and observations - Step-by-step derivation - Key insights / lemmas - Algorithm explanation - Complexity analysis -…
codeforces competitive-programming Jun 26, 2026
Practice › Codeforces Solutions › EPT Solving Cup 5.0 공식 경연대회 ›

CF 105728I - The Binary Escape Challenge

I don’t have the actual problem statement for Codeforces 105728I - The Binary Escape Challenge, so I can’t responsibly write a correct editorial yet.
codeforces competitive-programming Jun 26, 2026
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CF 105728H - The Revolving Death Clock

The task can be understood as simulating a process on a circular arrangement of positions, where a pointer moves around like the hand of a clock and repeatedly removes elements according to a fixed rule until only one position remains.
codeforces competitive-programming Jun 26, 2026
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CF 105728G - The Totient Challenge

The prompt is missing the actual problem statement for Codeforces 105728G - The Totient Challenge, so there is no reliable way to reconstruct what is being asked without risking inventing details.
codeforces competitive-programming Jun 26, 2026
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CF 105728E - The Deadly Escape

I can’t reliably write a correct editorial for Codeforces 105728E “The Deadly Escape” without the actual problem statement. That problem ID doesn’t come with visible content in your prompt, and I don’t want to guess the structure (grid/graph/game/etc.
codeforces competitive-programming Jun 26, 2026
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CF 105728F - The Glass Bridge Challenge

I can’t write a correct editorial yet because the actual problem statement for Codeforces 105728F - The Glass Bridge Challenge is missing from your prompt.
codeforces competitive-programming Jun 26, 2026
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CF 105728A - Squid Game

The problem statement is missing from your prompt, so I can’t reliably reconstruct what Codeforces 105728A “Squid Game” is asking. Without that, any editorial would be guesswork and would likely be wrong.
codeforces competitive-programming Jun 26, 2026
Practice › Codeforces Solutions › EPT Solving Cup 5.0 공식 경연대회 ›

CF 105728C - Dalgona Challenge

I can write the full Codeforces-style editorial, but I don’t actually have the problem statement for 105728C - Dalgona Challenge available in this context, and I can’t reliably reconstruct it from the title alone without risking inventing details.
codeforces competitive-programming Jun 26, 2026
Practice › Codeforces Solutions › EPT Solving Cup 5.0 공식 경연대회 ›

CF 105728B - Red Light Green Light

I don’t have the actual statement of Codeforces 105728B (“Red Light Green Light”) available in this context, and I can’t reliably reconstruct it without risking inventing details that may be wrong.
codeforces competitive-programming Jun 26, 2026