数据结构实验之查找二：平衡二叉树

Problem Description

根据给定的输入序列建立一棵平衡二叉树，求出建立的平衡二叉树的树根。

Input

输入一组测试数据。数据的第1行给出一个正整数N(n <= 20)，N表示输入序列的元素个数；第2行给出N个正整数，按数据给定顺序建立平衡二叉树。

Output

输出平衡二叉树的树根。

Example Input

588 70 61 96 120

Example Output

70

#include <stdio.h>#include <stdlib.h>#include <string.h>typedef int Elemtype;typedef struct node{    Elemtype data;    int d;    struct node *lchild,*rchild;};int max(int x,int y){    return x>y ? x:y;}int Deep(struct node *head){    if (!head)        return -1;    else return head->d;}struct node *LL(struct node *head)//右旋{ struct node *p = head->lchild; head->lchild = p->rchild; p->rchild = head; p->d = max(Deep(p->lchild),Deep(p->rchild))+1; head->d = max(Deep(head->lchild),Deep(head->rchild))+1; return p;}struct node *RR(struct node *head)//左旋{ struct node *p = head->rchild; head->rchild = p->lchild; p->lchild = head; p->d = max(Deep(p->lchild),Deep(p->rchild))+1; head->d = max(Deep(head->lchild),Deep(head->rchild))+1; return p;}struct node *LR(struct node *head){  head->lchild = RR(head->lchild);//先做左旋  return LL(head);//在做右旋}struct node *RL(struct node *head){ head->rchild = LL(head->rchild);//先做右旋 return RR(head);//在做左旋}struct node *Creat(struct node *head,int x){    if (head == NULL)    {        head = (struct node *)malloc (sizeof (struct node));        head->data = x;        head->d = 0;        head->rchild = head->lchild = NULL;    }    else if (head->data > x)    {        head->lchild = Creat(head->lchild,x);        if (Deep(head->lchild)-Deep(head->rchild)>1)        {            if (head->lchild->data > x)                head = LL(head);            else                head = LR(head);        }    }    else if (head->data < x)    {        head->rchild  = Creat(head->rchild,x);        if (Deep(head->rchild)-Deep(head->lchild)>1)        {            if (head->rchild->data > x)                head = RL(head);            else                head = RR(head);        }    }    head->d = max(Deep(head->lchild),Deep(head->rchild))+1;    return head;}int main(){    int n,m;    scanf ("%d",&n);    struct node *head = NULL;    for (int i=0; i<n; i++)    {        scanf ("%d",&m);        head = Creat(head,m);    }    printf ("%d\n",head->data);    return 0;}