004 -- Binary search Tree

000 - search tree 

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

#define datatype int
typedef struct Node{
datatype data;
struct Node *lchild;
struct Node *rchild;
}bintree;

//create tree 

bintree* createbinarytree(data)
{
  bintree* t = (bintree*)malloc(sizeof(bintree));
  if(!t)
  {
    printf("Not enough space
");
    return NULL;

  }
  t->lchild = NULL;
  t->rchild = NULL;
  t->data = data;
  return t;
}

bintree search_tree(bintree t, datatype x){
  if(!t)
    {return NULL;}
  if(t->data == x)
    return t;
  else:
    {
      if(!search_tree(t->lchild,x))
        {return search_tree(t->rchild,x);}

      return t;
    }

}

002 --  count the nodes in the tree 

int count_tree(bintree t)
{
  if(t)
  {
     return (count_tree(t->lchild)+ count_tree(t->rchild)+1);
  }

  return 0;


}

003 -- compare 2 binary trees 

int is_equal(bintree t1, bintree t2)
{
  if(!t1 && !t2)
  { return 1 ;} // both tree is empty, equal 

  if(t1 && t2 && t1-->data == t2->data) 
//one tree is empty or there is one data is different , then break 
  {
     if(is_equal(t1->lchild,t2->lchild))
       if(is_equal(t1->rchild, t2->rchild))
          { return 1;}
  }

   return 0;


}

004 - degree check of the tree 

int hight_tree(bintree t)
{
  int h, left, right;
  if(!t)
  {
    return 0;
  }

  left = high_tree(t->lchild);
  right = high_tree(t->rchild);
  h = (left>right ? left: right) +1;

  return h;
}

005- find a element in the binary search tree 

bintree* Find(datatype x, bintree t)
{
  while(t)
  {
    if(x>t->data)
      t = t->rchild;
    else if(x < t->data)
      t = t->lchild;
    else
      return t;
  }

  return NULL:
}

006 - find the min data in the binary search tree

bintree* FindMin(bintree* t)
{
  if(t)
  {
    while(t->lchild)
      t = t->lchild;
  }
  return t;

}

// same for the max 

bintree* FindMax(bintree* t)
{
  if(t)
  {
    while(t->rchild)
      t = t->rchild;
  }
  return t;

}

007 -- insert a node to the binary search tree 

bintree* Insert(bintree* t, datatype x)
{
  if(!t)
  {
    t = createbinarytree(x);
    t->lchild = NULL;
    t->rchild = NULL;
  }
  
  else
  {
    if(x>t->data)
      t ->rchild = Insert(x, t->rchild);
    else if 
      t->lchild = Insert(x, t->lchild);
  }

  return t;

}

008 -- delete a node 

BinaryTree* Delete(ElementType x, BinaryTree* BST) {  
    BinaryTree* Temp;  
    if (!BST)  
        printf("
didn't find the node to delete%d", x);  
    else if (x < BST->data)  
        BST->leftSubTree = Delete(x, BST->leftSubTree);  
    else if (x > BST->data)  
        BST->rightSubTree = Delete(x, BST->rightSubTree);  
    else { 
// find the node to be deleted
 
        if (BST->leftSubTree && BST->rightSubTree) { 
//the node has lchild and rchild
            Temp = FindMin(BST->rightSubTree); 
//find the min rchild to replace the deleted node
            BST->data = Temp->data;  
            BST->rightSubTree = Delete(BST->data, BST->rightSubTree);  //delete the rchild of the deleted node 
        }  
        else { //the deleted node has 1 or no child node 
            Temp = BST;  
            if (!BST->leftSubTree) //has rchild or no child 
                BST = BST->rightSubTree;  
            else if (!BST->rightSubTree) //has lchild or no child
                BST = BST->leftSubTree;  
            free(Temp);  
        }  
    }  
    return BST;  
}  
  

  
int main(int argc, const char * argv[]) {  
    bintree* t = createbinarytree(18);  
    Insert(10, t);  
    Insert(20, t);  
    Insert(7, t);  
    Insert(15, t);  
    Insert(9, t);  
    Insert(22, t);  
      
    bintree* findBT1 = Find(15, t);  
    if (findBT1) printf("find1：%d", findBT1->data);  
      
    bintree* findBT2 = Find(22, root);  
    if (findBT2) printf("
find2：%d", findBT2->data);  
      
    Delete(10, root);  
    bintree* findBT3 = Find(10, root);  
    if (findBT3) printf("
find3：%d", findBT3->data);  
      
    bintree* findBT4 = Find(9, root);  
    if (findBT4) printf("
find4：%d", findBT4->data);  
      
    Delete(9, root);  
    bintree* findBT5 = Find(9, root);  
    if (findBT5) printf("find5：%d", findBT5->data);  
      
    return 0;  
}  

More details:

http://www.cnblogs.com/elaron/archive/2013/04/11/3015155.html

http://www.cnblogs.com/fu11211129/p/4214047.html