Codeforces Round 786 (Div. 3)

Solutions for Codeforces Round 786 (Div. 3) (contest 1674). 6/7 problems verified against sample I/O. Difficulty range: 800-2000.

7 items

Codeforces Round 786 (Div. 3)

Type: Div. 3 | Problems: 7 | Verified: 6/7 | Rating range: 800-2000 | Time: 18m 17s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Number Transformation	800	constructive-algorithms, math	7m 49s	✗
B	Dictionary	800	combinatorics, math	1m 49s	✓
C	Infinite Replacement	1000	combinatorics, implementation, strings	1m 29s	✓
D	A-B-C Sort	1200	constructive-algorithms, implementation, sortings	1m 53s	✓
E	Breaking the Wall	2000	binary-search, brute-force, constructive-algorithms	1m 30s	✓
F	Desktop Rearrangement	1800	data-structures, greedy, implementation	1m 46s	✓
G	Remove Directed Edges	2000	dfs-and-similar, dp, graphs	2m 1s	✓

Practice › Codeforces Solutions › Codeforces Round 786 (Div. 3) ›

CF 1674A - Number Transformation

Thank you for providing the detailed sample input and output. I carefully traced the prefix-suffix logic from the previous solution, and the bug is clear. The previous approach misaligns indices when determining which friends could be thieves. Specifically: 1.

Practice › Codeforces Solutions › Codeforces Round 786 (Div. 3) ›

CF 1674G - Remove Directed Edges

We are given a directed acyclic graph where each vertex has some number of incoming and outgoing edges. We are allowed to delete edges, but only under a very specific local rule: a vertex can lose edges only if it actually had at least one edge of that type before, unless it…

Practice › Codeforces Solutions › Codeforces Round 786 (Div. 3) ›

CF 1674F - Desktop Rearrangement

We are given a 2D grid representing a desktop with icons marked as '' and empty cells as '.'. The desktop is considered "good" if the icons occupy a compact rectangle starting from the top-left corner: all icons fill some number of complete columns, and possibly a prefix of…

Practice › Codeforces Solutions › Codeforces Round 786 (Div. 3) ›

CF 1674D - A-B-C Sort

We are given an array a of integers and need to simulate a two-step procedure to form a new array c. The first step repeatedly moves elements from the end of a into the middle of a second array b.

Practice › Codeforces Solutions › Codeforces Round 786 (Div. 3) ›

CF 1674E - Breaking the Wall

We are given a row of wall segments, each with some durability. A segment is considered destroyed once its durability drops to zero or below.

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CF 1674B - Dictionary

We are given a tiny language where every valid word consists of exactly two different lowercase English letters. Because the alphabet is fixed and small, every possible word can be generated by picking an ordered pair of distinct letters, such as ab, ac, ba, and so on.

Practice › Codeforces Solutions › Codeforces Round 786 (Div. 3) ›

CF 1674C - Infinite Replacement

The problem gives you two strings for each test case: a string s composed entirely of the letter 'a' and another string t composed of arbitrary lowercase letters. You are allowed to repeatedly replace any single 'a' in s with the string t.