I need to find the longest depth in a multimap, I've tried everything I know and I'm lost at this point. I'd appreciate any help.


I have a program that connects 2 people. The connection is saved to a multimap as key value pair. for e.g `add john tim`  adds tim as a connection to john, tim can add more people and his connections can add more people.

I need to find the depth of a person’s subnetwork, that is, the longest recruitment chain starting from this person. For e.g, given the following set of data


    > add john mary
    > add john tom
    > add mary brad
    > add tom Maria
    > add mary Eli
    > add brad Sofia

`Depth John` should return 4, because the longest chain `John` has is 4.

`Mary, Brad, sofia, Eli` (4)

`tom -> Maria` (2)

and `Depth sofia` will return 1, since she's on her own and doesn't extend to anyone.

Here's what I've attempted.

 * for each key, find how many exists in the map (using equal_range)
 * then iterate through that and for each of them, count their depth
 * save the depth as the max and compare it after each iteration and return the max

Here is the code.

    void count_depth_recursive(std::multimap<std::string, std::string>networkMap, std::string id, int& depth)
    {

        auto range = networkMap.equal_range(id);
        for(auto it = range.first; it != range.second; ++it)
        {
            ++depth;
            std::cout  << it->second << std::endl;
            count_depth_recursive(networkMap, it->second, depth);
        }

    }

Driver function.

    int count_depth(std::multimap<std::string, std::string>networkMap, std::string id)
    {
        int depth = 0;
        int max = 0;

        if(networkMap.count(id) == 0)
        {
            return 1;
        }

        auto find = networkMap.equal_range(id);
        for(auto itr = find.first; itr != find.second; ++itr)
        {
            std::cout << "id is  " << itr->first <<" passing in: " << itr->second << std::endl;
            count_depth_recursive(networkMap, itr->first, depth);
            if(depth > max)
            {
                max = depth;
                depth = 0;
            }
            std::cout << "**************************************************************" << std::endl;

        }

        return max;
    }

I've been at it for ages now, I can't seem to figure out why it's not working.