### Denisson's blog

By Denisson, history, 11 months ago, translation, ,

Once again we apologize for making mistakes during preparation.

### 887A - Div. 64

Author: ayoyia.

If the string contains no ones then the answer is "NO" as the remainig number must be positive. Otherwise we can find the leftmost one and check if it is followed by at least six zeroes.

Solution.

### 887B - Cubes for Masha

Author: ayoyia.

The answer is always less or equal to 98. We can go through numbers from 1 to 99 and find the first one which we cannot make using cubes.

Solution.

### 887C - Solution for Cube

Author: ayoyia.

The amount of variants of input data for which the answer is "YES" is not more than 12 without considering rearrangement of colours. They all could be written in an array.

The alternative solution is writing a function of rotating a specific edge of the cube and checking if it is solved.

### 887D - Ratings and Reality Shows

Author: ayoyia.

We can create two arrays of prefix sums of events given in input. The first one on values (a, b) and the second one on values (c, d). The answer is either 0 or the moment of time right after an event occured. Let's use the method of two pointers. One pointer will indicate an event V after which we want to participate in the talk show and the other one at the moment of time right after its influence ends. Then we can participate in the talk show if the minimum of prefix sums on values (c, d) from elements between pointers is not less than the difference of prefix sums on values (a, b) and (c, d) from element V. Also we must check that Izabella's rating doesn't become negative before participating in the talk show or during its peroid of influence.

### 887E - Little Brother

Authors: ayoyia, Denisson.

The center of required circle is on a perpendicular to the middle of the segment AB where A and B are two points from the input. If a circle with the center on the segment AB and the radius equal to half of its length satisfies the conditions then it is the answer. Otherwise we can find on which side relative to AB the center of the circle is. Every drawn circle blocks a continious interval of allowed values for the requierd circle. The limits of this interval can be found by using binary search. Now we have to find the least allowed value for the radius. It can be done, for example, by using method of scanning line.

### 887F - Row of Models

Author: Denisson.

Time: O(n) or O(nlogn).

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By Denisson, history, 12 months ago, translation, ,

Hello Codeforces!

Round will start on Thursday, 3 November in 19:05 MSK.

Tasks are prepared by Anton Garder (ayoyia) and me, Shpakovskiy Denis (Denisson). Thanks to gainullin.ildar, glebodin, neckbosov, cdkrot, Arpa, Starcall for testing problems, gritukan for coordination and translation, MikeMirzayanov for Codeforces and Polygon platforms.

You will have six problems to solve in 2.5 hours.

Hope you will enjoy problems. Good luck to all!

Scoring: 500—1000—1500—2000—2500—3000

We want to apologise for mistakes in problem statements that led to round being unrated

Editorial.