数据结构1-树及常用算法

（一）将数据库存储结构转化为内存树型结构算法

public class TNode
{
    public string id { get; set; }
    public string pid { get; set; }
    public string name { get; set; }
    public string flag { get; set; }
}

public class Tree
{
    TNode node;
    public List<Tree> Children { get; set; }
}

public static Tree GetTreeList(List<TNode> data, string pid)
{
    Tree root = new Tree();
    List<TNode> item = data.FindAll(t => t.pid == pid); //查找父节点下的所有子节点
    if (item.Count == 0)
    {
        TNode temp = data.Find(t => t.id == pid);
        if (temp == null)
        {
            root = null;//空树
        }
        else
        {
            root.node = temp;
        }
    }
    if (item.Count > 0)
    {
        Tree p = new Tree();//当前节点父节点指针
        foreach (TNode entity in item)
        {
            Tree node = GetTreeList(data, entity.id);
            TNode pnode = data.Find(x => x.id == node.node.pid);
            if (pnode != null)
            {
                p.node = pnode;
                p.Children.Add(node);
                root = p;
            }
            else
            {
                root = node;
            }
        }
    }
    return root;
}