Educational Codeforces Round 189 (Rated for Div. 2)

7 problems from Educational Codeforces Round 189 (Rated for Div. 2) (contest 2225), difficulty -. 0/7 solutions verified against sample I/O.

7 items

Educational Codeforces Round 189 (Rated for Div. 2)

Div. 2 | 7 problems | 0/7 verified | Difficulty - | 11m 44s

# Problem Rating Tags Accepted Time ✓
A A Number Between Two Others greedy, math 17,509 1m 55s
B Alternating String brute-force, greedy 14,004 1m 36s
C Red-Black Pairs dp, greedy 11,219 1m 41s
D Exceptional Segments bitmasks, brute-force, math 6,550 1m 41s
E Covering Points with Circles constructive-algorithms, geometry, math 1,094 1m 34s
F String Cutting binary-search, brute-force, greedy 592 1m 51s
G Simple Problem brute-force, graphs, greedy 189 1m 26s
Practice › Codeforces Solutions › Educational Codeforces Round 189 (Rated for Div. 2) ›

CF 2225G - Simple Problem

We are given a set of integers from 0 to n − 1, and the task is to order them into a single sequence. The sequence must satisfy a local constraint: for every pair of consecutive elements in the permutation, their absolute difference must be divisible by at least one number…
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CF 2225F - String Cutting

We are given a string and we are allowed to split it into several consecutive pieces. Every piece must have length at least l, and we are required to produce at least k pieces in total. After choosing a valid cut, all resulting pieces are sorted lexicographically.
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CF 2225D - Exceptional Segments

We are working with the sequence of integers from 1 to n. From this sequence, we look at all contiguous subsegments that must contain a fixed position x. For every such segment, we compute the bitwise XOR of all elements inside it and check whether the result is exactly zero.
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CF 2225E - Covering Points with Circles

We are given a set of points on a 2D integer grid. These points are not adversarially structured; instead, they come from a random process inside a large axis-aligned square.
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CF 2225A - A Number Between Two Others

We are given two integers x and y such that y is greater than x and is divisible by x. The task is to determine whether there exists a third integer z that sits strictly between x and y, is divisible by x, but does not divide y.
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CF 2225C - Red-Black Pairs

We are given a grid with two rows and $n$ columns, so there are $2n$ cells in total. Each cell is colored either red or black.
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CF 2225B - Alternating String

We are given a binary string consisting only of a and b. The goal is to determine whether we can transform it into a perfectly alternating string, meaning no two adjacent characters are the same. We are allowed to perform at most one operation.
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