GATE1999-1.15

Question

The number of articulation points of the following graph is

• A. $0$
• B. $1$
• C. $2$
• D. $3$

Answer 1

ARTICULATION POINT: are those points whose removal from the graph makes the graph disconnected.

here if we remove the vertex no. $2$ than we get disconnected graph.

similarly if we remove the vertex no. $3$ than we get disconnected graph.

similarly if we remove the vertex no. $5$ than we get disconnected graph.

So, (D) choice. 

Comments

what about vertex no.1?

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vertex 1 is not cut vertex because if we remove it from a graph, a graph is still connected

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This is same as VERTEX CUT / SEPRATING SET

Answer 2

Answer: D

The articulation points are 2,3,5.