(b) Write the code for the function that computes and returns a vector containing the in-degrees of all vertices of a digraph given the adjacency list for the graph. Assume each adjacency list is a singly-linked, nullpos- terminated list of adjnodes. That is, in the last node the next field has value nullpos. struct adjnode t nt vertex; adjnode * next; vector vertex_indegrees2 (vector Adj) int nAdj.size // number of nodes int i, j adjnode cursor; // The vector to be returned: degree_vecvector vdegrees (n, 0)