平衡二叉搜索树/AVL二叉树 C实现

 1 #ifndef MY_AVLTREE_H
 2 #define MY_AVLTREE_H
 3 typedef int ElementType;
 4 struct TreeNode
 5 {
 6     ElementType data;
 7     struct TreeNode *left;
 8     struct TreeNode *right;
 9     int height;
10 };
11 typedef struct TreeNode TreeNode;
12 typedef TreeNode *Tree;
13 
14 Tree Find(ElementType e,Tree t);
15 Tree Insert(ElementType e,Tree t);
16 Tree Create();
17 //int Destroy();//这个没写。。。自己写下吧
18 Tree LeftRotate(Tree t);
19 Tree RightRotate(Tree t);
20 int Height(Tree t);
21 void Show(Tree t);
22 #endif

  1 #include <stdlib.h>
  2 #include <stdio.h>
  3 #include "AVLTree.h"
  4 #define MAX(a,b) ((a)>(b)?(a):(b))
  5 Tree Create()
  6 {
  7     Tree t=(Tree)malloc(sizeof(TreeNode));
  8     if(NULL==t)
  9     {
 10         printf("内存分配错误\n");
 11         return NULL;
 12     }
 13     t->data=0;
 14     t->left=NULL;
 15     t->right=NULL;
 16     t->height=0;
 17     return t;
 18 }
 19 Tree Find(ElementType e,Tree t)
 20 {
 21     if(NULL==t)
 22         return NULL;
 23     if(e==t->data)
 24         return t;
 25     else if(e>t->data)
 26         return Find(e,t->right);
 27     else
 28         return Find(e,t->left);
 29 }
 30 int Height(Tree t)
 31 {
 32     if(NULL==t)
 33         return -1;
 34     else
 35         return t->height;
 36 }
 37 Tree LeftRotate(Tree t)
 38 {
 39     
 40     if(NULL==t)
 41         return NULL; 
 42     Tree newtree=t->right;
 43     t->right=newtree->left;
 44     newtree->left=t;
 45     t->height=MAX(Height(t->left),Height(t->right))+1;
 46     newtree->height=MAX(Height(newtree->left),Height(newtree->right))+1;
 47     return newtree;
 48 }
 49 
 50 Tree RightRotate(Tree t)
 51 {
 52     if(NULL==t)
 53         return NULL;
 54     Tree newtree=t->left;
 55     t->left=newtree->right;
 56     newtree->right=t;
 57     t->height=MAX(Height(t->left),Height(t->right))+1;
 58     newtree->height=MAX(Height(newtree->left),Height(newtree->right))+1;
 59     return newtree;
 60 }
 61 
 62 Tree Insert(ElementType e,Tree t)
 63 {
 64     if(NULL==t)
 65     {
 66         Tree first=(Tree)malloc(sizeof(TreeNode));
 67         if(NULL==first)
 68         {
 69             printf("内存分配错误\n");
 70             return NULL;
 71         }
 72         first->left=NULL;
 73         first->right=NULL;
 74         first->height=0;
 75         first->data=e;
 76         return first;
 77     }
 78     if(e==t->data)
 79         {
 80             printf("元素已存在\n");
 81             return t;
 82         }
 83     if(e>t->data)
 84     {
 85         t->right=Insert(e,t->right);
 86         int left=Height(t->left);
 88         int right=Height(t->right);
 90         if(right-left==2)
 91             if (e<t->right->data)
 92             {
 93                 t->right=RightRotate(t->right);
 94                 t=LeftRotate(t);
 95             } 
 96             else
 97                 t=LeftRotate(t);
 98     }
 99     else
100     {
101         t->left=Insert(e,t->left);
102         int left=Height(t->left);
104         int right=Height(t->right);
106         if(left-right==2)
107             if (e>t->left->data)
108             {
109                 t->left=LeftRotate(t->left);
110                 t=RightRotate(t);
111             } 
112             else
113                 t=RightRotate(t);
114     }
115     t->height=MAX(Height(t->left),Height(t->right))+1;
116     return t;
117 }
118 void Show(Tree t)
119 {
120     if(t==NULL)
121         return;
122     Show(t->left);
123     printf("%d ",t->data);
124     Show(t->right);
125     
126     return;
127 }