Hi, I am having a hard time understanding the question.
Formally, we shall regard as Cthulhu such an undirected graph that can be represented as a set of three or more rooted trees, whose roots are connected by a simple cycle.
What does it mean to be "represented as a set of three or more rooted trees", whose roots are connected by a simple cycle? What is a "simple cycle"?
Can anyone who solved the problem give me a hint? Thank you!
Formally, we shall regard as Cthulhu such an undirected graph that can be represented as a set of three or more rooted trees, whose roots are connected by a simple cycle.
What does it mean to be "represented as a set of three or more rooted trees", whose roots are connected by a simple cycle? What is a "simple cycle"?
Can anyone who solved the problem give me a hint? Thank you!
Let us denote as a simple cycle a set of v vertices that can be numbered so that the edges will only exist between vertices number 1 and 2, 2 and 3, ..., v - 1 and v, v and 1.
A tree is a connected undirected graph consisting of n vertices and n - 1 edges (n > 0).
A rooted tree is a tree where one vertex is selected to be the root.
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That's written right at the bottom of the problem statement. Be sure to check it first next time.