二叉树的建立 插入 删除

二叉树

原文地址：二叉树节点的查找、插入、删除（C语言）作者：沁阳

#include <stdio.h>
#include <stdlib.h>

typedef int elemtype;
typedef struct Node
{
    elemtype data;
    struct Node *Lchild;
    struct Node *Rchild;
}TreeNode;
typedef TreeNode *bt;

int
Search_data(TreeNode *t,TreeNode **p,TreeNode **q, elemtype x)
{
    int flag=0;
    *p=NULL;
    *q=t;

    while(*q)
    {
        if (x>(*q)->data)
        {
            *p=*q;
            *q=(*q)->Rchild;
        }
        else{
            if (x<(*q)->data)
            {
                *p=*q;
                *q=(*q)->Lchild;
            }
            else{
                flag=1;
                break;                    
            }
        }
    }
    return flag;
}

int
InsertNode(TreeNode **t,elemtype x)
{
    int flag =0;
    TreeNode *q,*s;
    TreeNode *p=*t;

    if (!Search_data(*t,&p,&q,x))
    {
        s=(TreeNode *)malloc(sizeof(TreeNode));
        s->data=x;
        s->Lchild=NULL;
        s->Rchild=NULL;
        flag=1;
        if(!p) t=s;
        else{
            if(x>p->data)
                p->Rchild=s;
            else
                p->Lchild=s;
        }
    }
    return flag;
}

int
DeleteNode(TreeNode **t,elemtype x)
{
    int flag=0;
    TreeNode *q,*s,**f;
    TreeNode *p=*t;
    
    if (Search_data(*t,&p,&q,x))
    {
        flag=1;
        if(p==q) f=&(*t);
        else
        {
            f=&(p->Lchild);
            if(x>p->data)
                f=&(p->Rchild);
        }
        
        if(!q->Rchild)
            *f=q->Lchild;
        else{
            if(!q->Lchild)
                *f=q->Rchild;
            else{
                p=q->Rchild;
                s=p;
                while(p->Lchild){
                    s=p;
                    p=q->Lchild;
                }
                *f=p;
                p->Lchild=q->Lchild;

                if (s!=p)
                {
                    s->Lchild=p->Rchild;
                    p->Rchild=q->Rchild;
                }
            }
        }
        free(q);
    }
    return flag;
}


void
visit(bt t)
{
    printf("%c",t->data);
}

TreeNode *
creat_Tree()
{
    char ch;
    bt t;
    ch=getchar();
    if(ch==' ') return (NULL);
    else{
        t=(TreeNode *)malloc(sizeof(TreeNode));
        t->data=ch;
        t->Lchild=creat_Tree();
        t->Rchild=creat_Tree();
        printf("%xn",&t);
        return (t);
    }
}

void
mid_oderTree(bt t)
{
    if (t!=NULL)
    {
        mid_oderTree(t->Lchild);
        visit(t);
        mid_oderTree(t->Rchild);
    }
}

int
count_leafTree(bt t)
{
    int i;
    if(t==NULL) return 0;
    else
        if(t->Lchild==NULL&&t->Rchild==NULL)
            i=1;
        else i=count_leafTree(t->Lchild)+
            count_leafTree(t->Rchild);
        return i;
}

main()
{
    TreeNode  *t,*p,*q;
    elemtype x;
    x='M';
    printf("creat Tree:n");
    //二叉树在遍历最后一个节点之后，遇到结束符结束建立树。
    t=creat_Tree();
    printf("中根遍历树:n");
    mid_oderTree(t);
    
    printf("n中根序插入%c成功输出（是1否0）:%dn",x,InsertNode(&t,x));
    
    printf("插入%c后的查找成功输出（是1否0）：%dn",x,Search_data(t,&p,&q, x));
    printf("插入后的中根遍历树:n");
    mid_oderTree(t);
    
    printf("n删除%c成功输出（是1否0）：%d n",x,DeleteNode(&t,x));
    printf("删除后的中根遍历树:n");
    mid_oderTree(t);

    printf("n求树的叶子数:%d n",count_leafTree(t));
}