Degree Of Node

    

    The degree of a vertex V in a graph is defined as the number of graph edges that touches the vertex V.

     

    In a graph,

        the total sum of all degree of

       vertex = 2 * E    [E = number of edge]

    For a Tree,

        the total sum of all degree of

       vertex = 2 * E

              = 2 * (n-1)

 So if the sum of all degree of 

  vertex = 2*(n-1) then it must be a tree

    Related Problem:

         Monk at the Graph Factory