二叉查找树实现

二叉查找树声明

#ifndef _Tree_H

struct TreeNode;
typedef struct TreeNode *Position;
typedef struct TreeNode *SearchTree;

SearchTree MakeEmpty(SearchTree T);
Position Find( ElementType X,SearchTree T);
Position FindMin(SearchTree T);
Position FindMax( SearchTree T);
SearchTree Insert(ElementType X,SearchTree T);
SearchTree Delete(ElementType X,SearchTree T);
ElementType Retrieve( Position P);

#endif

srtuct TreeNode
{
	ElementType Element;
	SearchTree Left;
	SearchTree Right;
};

建立一颗空树

SearchTree MakeEmpty(SearchTree T)
{
	if(T != NULL)
	{
		MakeEmpty(T->Left);
		MakeEmpty(T->Right);
		Free(T);
	}
	return NULL;
}

二叉查找树的Find操作

Position Find(ElementType X,SearchTree T)
{
	if(T == NULL)
		return NULL;
	if( X < T->Element)
		return Find(X,T->Left)
	else if( X > T->Element)
		return Find(X,T->Right)
	else return T;
}

二叉查找树的FindMin递归实现

Position FindMin(SearchTree T)
{
	if(T == NULL)
		return NULL;
	else if( T->Left == NULL)
		return T;
	else
		return FindMin(T->Left);
}

二叉查找树的FindMin非递归实现

Position FindMin(SearchTree T)
{
	if(T != NULL)
		while(T->Left != NULL)
			T = T->Left;
	return T;
}

二叉查找树的FindMax递归实现

Position FindMax(SearchTree T)
{
	if(T == NULL)
		return NULL;
	else if( T->Right == NULL)
		return T;
	else
		return FindMax(T->Right);
}

二叉查找树的FindMax非递归实现

Position FindMax(SearchTree T)
{
	if(T != NULL)
		while(T->Right != NULL)
			T = T->Right;
	return T;
}

二叉查找树的插入操作

SearchTree Insert(ElementType X,SearchTree T)
{
	if(T == NULL)
	{
		T = malloc(sizeof(struct TreeNode));
		if(T == NULL)
			FatalError("Out of space!!!");
		else
		{
			T->Element = X;
			T->Left = T->Right = NULL;
		}
	}
	else if(X < T->Element)
		T->Left = Insert(X,T->Left);
	else if( X > T->Element)
		T->Right = Insert(X,T->Right);
	return T;
}

二叉查找树的删除操作

SearchType Delete(ElementType X,SearchTree T)
{
	Position TmpCell;
	if(T == NULL)
		Error("Element not found");
	else if(X < T->Element)
		T->Left = Delete(X,T->Left);
	else if(X > T->Element)
		T->Right = Delete(X,T->Right);
	else if(T->Left && T->Right)
	{
		TmpCell = FindMin(T->Right);
		T->Element = TmpCell->Element;
		T->Right = Delete(T->Element,T->Right);
	}
	else
	{
		TmpCell = T;
		if(T->Left == NULL)
			T = T->Right;
		else if(T->Right == NULL)
			T = T->Left;
		free(TmpCell);
	}
	return T;
}