Educational Codeforces Round 185 (Rated for Div. 2)

6 problems from Educational Codeforces Round 185 (Rated for Div. 2) (contest 2170), difficulty 800-2600. 3/6 solutions verified against sample I/O.

6 items

Educational Codeforces Round 185 (Rated for Div. 2)

Div. 2 | 6 problems | 3/6 verified | Difficulty 800-2600 | 11m 38s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Maximum Neighborhood	800	bitmasks, brute-force, greedy	19,887	1m 43s	✓
B	Addition on a Segment	1200	greedy, math	14,276	1m 59s	✓
C	Quotient and Remainder	1300	binary-search, greedy, two-pointers	11,236	1m 22s	✓
D	Almost Roman	2200	constructive-algorithms, greedy, implementation	1,680	1m 47s
E	Binary Strings and Blocks	2100	combinatorics, data-structures, dp	2,317	2m 21s
F	Build XOR on a Segment	2600	bitmasks, dp	777	2m 26s

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CF 2170F - Build XOR on a Segment

We are asked to process multiple queries on an array of integers, where each query specifies a segment of the array and a target number. For each query, we need to find the smallest subset of elements within that segment whose XOR equals the target.

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CF 2170E - Binary Strings and Blocks

We are asked to count binary strings of length n that satisfy multiple “beauty” constraints on certain substrings. A block is a maximal contiguous sequence of identical characters.

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CF 2170D - Almost Roman

We are given a string consisting of the characters 'X', 'V', 'I', and '?'. Each letter has a numeric value: 'X' is worth 10, 'V' is worth 5, and 'I' is usually worth 1, but if it is immediately followed by an 'X' or 'V', it counts as -1.

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CF 2170B - Addition on a Segment

We are given an array of length $n$, initially all zeros. We perform exactly $n$ operations, and each operation adds $1$ to every element of some chosen contiguous segment.

Practice › Codeforces Solutions › Educational Codeforces Round 185 (Rated for Div. 2) ›

CF 2170A - Maximum Neighborhood

We are asked to consider an $n times n$ grid of integers filled sequentially row by row. The first row contains numbers from $1$ to $n$, the second from $n+1$ to $2n$, and so on until the $n$-th row, which contains numbers from $n^2-n+1$ to $n^2$.

Practice › Codeforces Solutions › Educational Codeforces Round 185 (Rated for Div. 2) ›

CF 2170C - Quotient and Remainder

We are given two multisets of integers, one called $q$ and one called $r$, along with an upper bound $k$. The only way to remove elements is by pairing one value from $q$ with one value from $r$ through a hidden construction involving two integers $x$ and $y$, where $1 le y <…