df.c Actully Introduces A Way To Think Of Algorithm

[lin zuojian <manjian2006 at gmail dot com>]

Hi,
    I don't know if this is mentioned before, df.c is introducing a very
    good way to think of algorithms. It brings two effective orders to
    handle many problems: DF_FORWARD and DF_BACKWARD. They means two
    fact respectively: a subproblem will not be accessed until all
    its parents get accessed; And a problem will not be accessed until
    all its subproblems get accessed.
    
    The single source shortest path will have a O(n) solution instead of
    O(n + log(n)) if using DF_FORWARD. Defining
    df_confluence_function_n like following:
    {
        if(e->wight + e->src->total_wight < e.dest->total_wight)
            {
                e->dest.total_wight = e->wight + e->src->total_wight;
                e->dest.parent = e->src;
            }
    }

    I think it's really O(n) for a dfs right?
    That's what I want to proposed.
--
Lin Zuojian