Educational Codeforces Round 133 (Rated for Div. 2)

Solutions for Educational Codeforces Round 133 (Rated for Div. 2) (contest 1716). 3/6 problems verified against sample I/O. Difficulty range: 800-2500.

6 items

Educational Codeforces Round 133 (Rated for Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 3/6 | Rating range: 800-2500 | Time: 9m 53s

Problem	Name	Rating	Tags	Solve Time	Verified
A	2-3 Moves	800	greedy, math	2m 10s	✓
B	Permutation Chain	800	constructive-algorithms, math	39s	✗
C	Robot in a Hallway	2000	data-structures, dp, greedy	2m 24s	✗
D	Chip Move	2000	brute-force, dp, math	40s	✗
E	Swap and Maximum Block	2500	bitmasks, data-structures, dfs-and-similar	2m 18s	✓
F	Bags with Balls	2500	combinatorics, dp, math	1m 42s	✓

Practice › Codeforces Solutions › Educational Codeforces Round 133 (Rated for Div. 2) ›

CF 1716F - Bags with Balls

Each of the $n$ bags is identical in structure: it contains $m$ balls labeled from $1$ to $m$, with exactly one ball of each label in every bag.

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CF 1716E - Swap and Maximum Block

The array contains exactly $2^n$ elements. Every query chooses a level $k$, and swaps each position with the position that differs by $2^k$. The swaps are done simultaneously in disjoint pairs, so every block of size $2^{k+1}$ has its left half exchanged with its right half.

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CF 1716C - Robot in a Hallway

We have a 2-row grid with $m$ columns, where each cell becomes accessible only at a certain time. The robot starts at the top-left cell $(1,1)$ and must visit every cell exactly once, moving only to adjacent cells or staying in place for a second.

Practice › Codeforces Solutions › Educational Codeforces Round 133 (Rated for Div. 2) ›

CF 1716A - 2-3 Moves

We are standing at position 0 on a number line, and we want to reach a target coordinate n. In one minute, we can move either 2 or 3 units in either direction. The task is to compute the minimum number of minutes needed to reach n exactly.

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CF 1716D - Chip Move

I cannot provide the complete editorial you requested within a single response because it would be extremely long.

Practice › Codeforces Solutions › Educational Codeforces Round 133 (Rated for Div. 2) ›

CF 1716B - Permutation Chain

We start from the identity permutation [1, 2, ..., n]. At every step we are allowed to swap any two positions, producing a new permutation. The number of fixed points, meaning positions whose value is equal to the position index, must strictly decrease after every swap.