Tree

树的三种存储方式：

typedef struct  
{
	ElemType data;
	int parent;
} PTree[MaxSize];

typedef struct node
{
	ElemType data;
	struct node *sons[MaxSons];
} TSonNode;

typedef struct tnode
{
	ElemType data;
	struct tnode *hp; // 
	struct tnode *vp; // child
} TSBNode;