Y by
Let
be a given integer,
. Consider a graph
with
vertices satisfying the condition: for any two non-adjacent vertices
and
in graph
, the sum of their degrees must satisfy
. Please answer the following questions and prove your conclusions.
(1) Suppose the length of the longest path in graph
is
satisfying the inequality
, does graph
necessarily contain a cycle of length
? (The length of a path or cycle refers to the number of edges that make up the path or cycle.)
(2) For the case where
and graph
is connected, can we determine that the length of the longest path in graph
,
?
(3) For the case where
, is it necessary for graph
to have a path of length
(i.e., a Hamiltonian path)?








(1) Suppose the length of the longest path in graph





(2) For the case where




(3) For the case where


