Educational Codeforces Round 119 (Rated for Div. 2)

Solutions for Educational Codeforces Round 119 (Rated for Div. 2) (contest 1620). 2/7 problems verified against sample I/O. Difficulty range: 800-2800.

7 items

Educational Codeforces Round 119 (Rated for Div. 2)

Type: Div. 2 | Problems: 7 | Verified: 2/7 | Rating range: 800-2800 | Time: 19m 29s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Equal or Not Equal	800	constructive-algorithms, dsu, implementation	3m 41s	✗
B	Triangles on a Rectangle	1000	geometry, greedy, math	1m 16s	✓
C	BA-String	1800	brute-force, dp, greedy	8m 11s	✗
D	Exact Change	2000	brute-force, constructive-algorithms, greedy	1m 31s	✗
E	Replace the Numbers	1900	constructive-algorithms, data-structures, dsu	1m 34s	✗
F	Bipartite Array	2800	dp, greedy	1m 45s	✗
G	Subsequences Galore	2400	bitmasks, combinatorics, dp	1m 31s	✓

Practice › Codeforces Solutions › Educational Codeforces Round 119 (Rated for Div. 2) ›

CF 1620C - BA-String

Ah! Now I understand exactly what’s happening. The previous “solutions” were just printing the raw input values because the code never implemented the grid placement / R-painting logic. That explains why your actual output is literally the input.

Practice › Codeforces Solutions › Educational Codeforces Round 119 (Rated for Div. 2) ›

CF 1620G - Subsequences Galore

We are given up to 23 strings. Each string is already “sorted” in the sense that it is grouped by character, so it looks like a run-length encoding over 'a'..'z', for example "aaabccczzz". Now consider any subset of these strings.

Practice › Codeforces Solutions › Educational Codeforces Round 119 (Rated for Div. 2) ›

CF 1620F - Bipartite Array

We are given a permutation, and we are allowed to independently flip the sign of each element. So each value becomes either positive or negative, but its magnitude stays the same and every absolute value from 1 to n still appears exactly once.

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CF 1620E - Replace the Numbers

We start with an empty sequence and process a stream of operations that either append a value to the end or globally rename every occurrence of one value into another. The final task is to output the resulting sequence after all operations have been applied.

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CF 1620A - Equal or Not Equal

We are given a circular array of positive integers, and for each adjacent pair in the circle, we know whether the numbers are equal or not.

Practice › Codeforces Solutions › Educational Codeforces Round 119 (Rated for Div. 2) ›

CF 1620D - Exact Change

We are asked to prepare coins in advance so that no matter which bag of chips we choose from the store, we can pay the exact price using only coins of denominations 1, 2, and 3. The input for each test case gives the number of flavors and the cost of each flavor.

Practice › Codeforces Solutions › Educational Codeforces Round 119 (Rated for Div. 2) ›

CF 1620B - Triangles on a Rectangle

We are asked to select three points on the boundary of a rectangle to form a triangle with maximum possible area, with the restriction that exactly two of the points lie on the same side.