ICPC Central Russia Regional Contest (CRRC 18)

11 problems from ICPC Central Russia Regional Contest (CRRC 18) (contest 102785), difficulty -. 9/11 solutions verified against sample I/O.

11 items

ICPC Central Russia Regional Contest (CRRC 18)

ICPC/IOI | 11 problems | 9/11 verified | Difficulty - | 11m 3s

#	Problem	Time	✓
A	A lazy controller	59s	✓
B	Gremlins attack!	46s	✓
C	Dimensions	1m 36s	✓
D	We were trying to share an orange ...	1m 15s	✓
E	Hanoi Tower	29s
F	Pebbles	1m 27s	✓
G	Non-random numbers	57s	✓
H	A self-describing sequence	1m 12s	✓
I	Noughts and crosses	26s
J	R u really ready?	48s	✓
K	Meson Collider	1m 8s	✓

Practice › Codeforces Solutions › ICPC Central Russia Regional Contest (CRRC 18) ›

CF 102785I - Noughts and crosses

Producing a correct editorial for this problem requires first deriving and verifying the actual algorithm. The prompt asks for a complete editorial, a proven-correct Python implementation, worked traces, complexity proof, and assert-based tests.

Practice › Codeforces Solutions › ICPC Central Russia Regional Contest (CRRC 18) ›

CF 102785A - A lazy controller

Each weighing records two integers. The first is the number of identical parts placed on the scale, and the second is the measured total weight of those parts. If every part in the batch has the same integer weight x, then every record must satisfy wi = ai × x.

Practice › Codeforces Solutions › ICPC Central Russia Regional Contest (CRRC 18) ›

CF 102785E - Hanoi Tower

I'm missing one critical piece needed to write a correct editorial: the sample input/output in the prompt is blank, and more importantly, the original statement does not explicitly specify the order of the binary string (whether the first character corresponds to the smallest…

Practice › Codeforces Solutions › ICPC Central Russia Regional Contest (CRRC 18) ›

CF 102785F - Pebbles

The hidden parameters of the game are the value added on each move, a, and the losing threshold, n. For every remembered starting pile size s, we know whether the first player wins or loses.

Practice › Codeforces Solutions › ICPC Central Russia Regional Contest (CRRC 18) ›

CF 102785B - Gremlins attack!

We have an N x N board of houses. Some cells contain gremlins at the beginning. Every cell starts with its light on, so gremlins cannot move through it. Over time, the history describes cells whose lights are switched off. After a cell becomes dark, it remains available forever.

Practice › Codeforces Solutions › ICPC Central Russia Regional Contest (CRRC 18) ›

CF 102785K - Meson Collider

We have four spark chambers placed on the circumference of a circle with radius R. The input gives the four consecutive angular gaps between them, so we can reconstruct the four points on the circle.

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CF 102785J - R u really ready?

The task is to decide whether a text string can be generated by a pattern string. The pattern is made of ordinary lowercase letters and optional repetition symbols.

Practice › Codeforces Solutions › ICPC Central Russia Regional Contest (CRRC 18) ›

CF 102785H - A self-describing sequence

We need construct a sequence of length k such that every position describes how often its index appears inside the whole sequence. If the value at position i is x, then the number i must occur exactly x times among all elements.

Practice › Codeforces Solutions › ICPC Central Russia Regional Contest (CRRC 18) ›

CF 102785G - Non-random numbers

The input describes a local rule on a binary sequence. The rule is written as a Boolean expression where a digit r means the bit that is r positions before the current bit. For example, 0 represents the current bit, 1 represents the previous bit, and so on.

Practice › Codeforces Solutions › ICPC Central Russia Regional Contest (CRRC 18) ›

CF 102785D - We were trying to share an orange ...

The orange is described only through the number of slices it has. A company with x people can share the orange exactly when the number of slices is divisible by x, so the valid company sizes are exactly the positive divisors of the slice count.

Practice › Codeforces Solutions › ICPC Central Russia Regional Contest (CRRC 18) ›

CF 102785C - Dimensions

Edit The input is a mathematical expression describing a physical dimension. Every Latin letter represents a basic dimension, while multiplication, division, and parentheses combine dimensions in the usual way.