树和而叉查找树的实现
1.树节点的典型声明
typedef struct TreeNode *PtrToNode;
struct TreeNode
{
ElementType Element;
PtrToNode FirstChild;
PtrToNode NextSibling; /* 指向下一个兄弟 */
}
2.而叉查找树的实现
#include <stdio.h>
#include <stdlib.h>
struct TreeNode;
typedef struct TreeNode *SearchTree;
typedef struct TreeNode *Position;
struct TreeNode
{
int Element;
SearchTree Left;
SearchTree Right;
};
/* 清空＆初始化树 */
SearchTree MakeEmpty(SearchTree T)
{
if (T != NULL)
{
MakeEmpty(T->Left);
MakeEmpty(T->Right);
free(T);
}
return NULL;
}
/* 在树中查找x */
Position Find(int 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;
}
/* 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);
}
/* 非递归实现 */
Position FindMax(SearchTree T)
{
if (T != NULL)
while (T->Right != NULL)
T = T->Right;
return T;
}
/* 将元素插入树 */
SearchTree Insert(int x, SearchTree T)
{
if (T == NULL)
{
T = malloc(sizeof(struct TreeNode));
if (T == NULL)
printf("Out of space!\n");
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;
}
/* 在树中查找x,并删除 */
SearchTree Delete(int x, SearchTree T)
{
Position TmpCell;
if (T == NULL)
printf("Element not found!\n");
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;
}
int main()
{
SearchTree tree = NULL;
MakeEmpty(tree);
/* 注意Insert返回值为树 */
tree = Insert(3, tree);
tree = Insert(1, tree);
tree = Insert(2, tree);
tree = Insert(4, tree);
Position p;
p = FindMin(tree);
printf("Min = %d\n", p->Element);
p = FindMax(tree);
printf("Max = %d\n", p->Element);
p = Find(1, tree);
if (p != NULL)
{
printf("Find %d success!\n", p->Element);
}
else
{
printf("Do not find in tree!\n");
}
tree = Delete(1, tree);
p = FindMin(tree);
printf("Min = %d\n", p->Element);
return 0;
}