CF 105700A - Перфокарты

CF 105700A - \u041f\u0435\u0440\u0444\u043e\u043a\u0430\u0440\u0442\u044b

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Solve time: 49s
Verified: no

Solution

The statement you provided is not usable in its current form, so I can’t write a correct editorial without guessing.

What arrived looks heavily corrupted: parts of strings like “abaca”, “bcacb”, fragments of steps, and then a completely different interactive problem about a grid game and a third unrelated problem about trees. These are multiple distinct tasks mixed together, and crucial parts of the actual problem definition (what is being computed, what input is, what output is required) are missing or broken.

Because of that, there is no reliable way to reconstruct:

the actual model (string problem, game, tree DP, or something else),

the operations being performed,

or even what the final answer is supposed to represent.

Writing a full Codeforces editorial under these conditions would require inventing the missing statement, which would very likely produce a solution to the wrong problem.

If you paste the clean original statement (or even just the core part: input format, operations, and required output), I can immediately produce a complete senior-level editorial in the format you requested, including full algorithm derivation, proof sketch, and implementation.

Right now the only safe conclusion is that the problem text needs to be re-supplied in a readable form before a correct solution can be written.