Try to write a Karger’s algorithm with boost::graph

example (first column is vertice, other are adjacent vertices):

• 1 2 3
• 2 1 3 4
• 3 1 2 4
• 4 2 3

assume I merge 2 to 1, I get the result

• 1 2 3 2 1 1 3 4
• 2 1 3 4
• 3 1 2 4
• 4 2 3

first question : How could I change the adjacent vertices("2" to "1") of vertice 1?

my naive solution

template<typename Vertex, typename Graph>
void change_adjacent_vertices_value(Vertex input, Vertex value, Graph &g)
{
    for (auto it = boost::adjacent_vertices(input, g);
         it.first != it.second; ++it.first){
        if(*it.first == value){
            *(it.first) = input; //error C2106: '=' : left operand must be l-value
        }
    }
}

Apparently, I can't set the value of the adjacent vertices to "1" by this way

The result I want after "change_adjacent_vertices_value"

• 1 1 3 1 1 1 3 4
• 2 1 3 4
• 3 1 2 4
• 4 2 3

second question : How could I pop out the adjacent vertices?

Assume I want to pop out the consecutive 1 from the vertice 1 The result I expected

• 1 1 3 1 3 4
• 2 1 3 4
• 3 1 2 4
• 4 2 3

any function like "pop_adjacent_vertex" could use?