使用C语言构建基本的二叉树数据结构

#include#includetypedef struct Node{ int data; Node *leftchild; Node *rightchild;}Node;/* 初始化一棵二叉树排序树。*/void InitBinaryTree(Node**root,int elem){ *root=(Node*)malloc(sizeof(Node)); if(!(*root)) { printf("Memory allocation for root failed./n"); return; } (*root)->data=elem; (*root)->leftchild=NULL; (*root)->rightchild=NULL;}/* 向二叉树排序树中插入节点。*/void InsertNode(Node *root,int elem){ Node *newnode=NULL; Node *p=root,*last_p=NULL; newnode=(Node*)malloc(sizeof(Node)); if(!newnode) { printf("Memory allocation for newnode failed./n"); return; } newnode->data=elem; newnode->leftchild=NULL; newnode->rightchild=NULL; while(NULL!=p) { last_p=p; if(newnode->datadata) { p=p->leftchild; } else if(newnode->data>p->data) { p=p->rightchild; } else { printf("Node to be inserted has existed./n"); free(newnode); return; } } p=last_p; if(newnode->datadata) { p->leftchild=newnode; } else { p->rightchild=newnode; }}/* 创建一棵二叉树排序树。*/void CreatBinarySearchTree(Node **root,int data[],int num){ int i; for(i=0;i { if(NULL==*root) { InitBinaryTree(root,data[i]); } else { InsertNode(*root,data[i]); } }}

 bt rebuildTree(char *pre, char *in, int len); 

 /**   * Description:根据前序和中序构建二叉树   */  bt rebuildTree(char *pre, char *in, int len)  {   bt t;   if(len <= 0)   {    //递归终止    t = NULL;   }else   {    //递归主体    int index = 0;        while(index < len && *(pre) != *(in + index))    {     index ++;    }        if(index >= len)    {     printf("前序遍历或者中序遍历数组有问题!/n");     exit(-1);    }        t = (struct bintree *)malloc(sizeof(struct bintree));    t->item = *pre;    t->lchild = rebuildTree(pre + 1, in, index);    t->rchild = rebuildTree(pre + (index + 1), in + (index + 1), len - (index + 1));   }   return t;  } 

 /**   * 中序、后序序列构建二叉树   */  btree* rebuildTree(char *order, char *post, int len); 

 /**   * 根据中序和后序序列构建二叉树   * (ps:昨晚参加阿里笔试，等到最后说可以免笔试直接面试，今天估计还是要根据学校筛选，哈哈，为了这点   * 也得参加阿里笔试，不能让自己的学校受到鄙视)   */    #include <stdio.h>  #include <stdlib.h>  #include <string.h>    int n;    typedef struct btree {   struct btree *lchild;   struct btree *rchild;   char data;  } btree;    /**   * 中序、后序序列构建二叉树   */  btree* rebuildTree(char *order, char *post, int len)  {   btree *t;     if (len <= 0) {    return NULL;   } else {    int index = 0;      while (index < len && *(post + len - 1) != *(order + index)) {     index ++;    }       t = (btree *)malloc(sizeof(btree));    t->data = *(order + index);    t->lchild = rebuildTree(order, post, index);    t->rchild = rebuildTree(order + index + 1, post + index, len - (index + 1));   }     return t;  }    /**   * 前序遍历二叉树   */  void preTraverse(btree *t)  {   if (t) {    printf("%c ", t->data);    preTraverse(t->lchild);    preTraverse(t->rchild);   }  }    int main(void)  {   int i;   char *post, *order;   btree *t;     while (scanf("%d", &n) != EOF) {    post = (char *)malloc(n);    order = (char *)malloc(n);        getchar();    for (i = 0; i < n; i ++)     scanf("%c", order + i);      getchar();    for (i = 0; i < n; i ++)     scanf("%c", post + i);      t = rebuildTree(order, post, n);      preTraverse(t);    printf("/n");      free(post);    free(order);     }     return 0;  }