Codeforces Round 656 (Div. 3)

7 problems from Codeforces Round 656 (Div. 3) (contest 1385), difficulty 800-2300. 0/7 solutions verified against sample I/O.

7 items

Codeforces Round 656 (Div. 3)

Div. 3 | 7 problems | 0/7 verified | Difficulty 800-2300 | 34m 47s

#	Problem	Rating	Tags	Accepted	Time
A	A	800	math	43,323	4m 30s
B	Restore the Permutation by Merger	800	greedy	39,577	2m 55s
C	Make It Good	1200	greedy	28,910	4m 8s
D	a-Good String	1500	bitmasks, brute-force, divide-and-conquer	21,953	8m 44s
E	Directing Edges	2000	constructive-algorithms, dfs-and-similar, graphs	9,017	5m 5s
F	Removing Leaves	2300	data-structures, greedy, implementation	2,820	7m 50s
G	Columns Swaps	2300	2-sat, dfs-and-similar, dsu	1,815	1m 35s

Practice › Codeforces Solutions › Codeforces Round 656 (Div. 3) ›

CF 1385E - Directing Edges

We are given a graph where every edge already knows its endpoints, but not all edges are allowed to choose their direction freely. Some edges are already directed and must stay exactly as they are, while the remaining edges are undirected and can be oriented however we want.

Practice › Codeforces Solutions › Codeforces Round 656 (Div. 3) ›

CF 1385G - Columns Swaps

We are given a two-row table with $n$ columns, and every cell contains a number between $1$ and $n$. In each column we are allowed to either leave the two values as they are or swap them, and each column can be swapped at most once.

Practice › Codeforces Solutions › Codeforces Round 656 (Div. 3) ›

CF 1385F - Removing Leaves

We are working with a tree where vertices are gradually removed in rounds. In one round, we are allowed to pick a single internal vertex $v$ and remove exactly $k$ of its current leaf neighbors. A vertex counts as a leaf if it has degree one in the current remaining graph.

Practice › Codeforces Solutions › Codeforces Round 656 (Div. 3) ›

CF 1385D - a-Good String

The task is to transform a given string into a very specific recursively defined structure centered around the letter 'a'.

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CF 1385C - Make It Good

We are given an array and we are only allowed to delete a prefix, meaning we remove some number of elements from the front and keep the rest unchanged.

Practice › Codeforces Solutions › Codeforces Round 656 (Div. 3) ›

CF 1385B - Restore the Permutation by Merger

We are given an array of length $2n$. This array was created by taking a permutation $p$ of the numbers $1$ through $n$, making a second copy of the same permutation, and interleaving the two copies while preserving the relative order inside each copy.