8

 / /

 6 10

/ / / /

5 7 9 11

#include "stdio.h"
#include "stdlib.h"
 
//二叉树节点
#define size 7
 
//二叉树节点定义
typedef struct node
{
  int data;
  struct node *left;
  struct node *right;
}BTree;
 
int printLine(BTree * root);
BTree * CreatTree(int a[],int n);
 
int main(void)
{
 
    int array[size] = {8,6,10,5,7,9,11};
    BTree * root;
 
    root = CreatTree(array,size);
  printLine(root);  
 
    printf("\n");
  return 0;
}
 
int printLine(BTree * root)
{
  BTree * queue[size], *p;
  int front,rear;
  front = rear = 0;
   
   
   
  rear = (rear+1)%size;
  queue[rear] = root;  
 
    //循环结束为队列为空
  while(front != rear)
  {    
      //根出队列
    front = (front +1)%size;
    p = queue[front];
    printf("%3d",p->data);
 
    //左孩子不空，队不满入队
    if(p->left && ((rear+1)%size != front))
    {
      rear = (rear+1)%size;
      queue[rear] = p->left;
    }
         
        //右孩子不空，队不满入队
    if(p->right && ((rear+1)%size != front))
    {
      rear = (rear+1)%size;
      queue[rear] = p->right;
    }
         
        //队满，报错
    if((rear+1)%size == front)
    {
      printf("队列空间不足，错误....\n");
      return 0;
    }
  }
 
  return 1;
}
 
//根据数组创建二叉排序树
BTree * CreatTree(int a[],int n)
{
    BTree * root ,*p,*cu,*pa;
    int i;
 
    root = (BTree *)malloc(sizeof(BTree));
    root->data = a[0];
    root->left = root->right =NULL;
 
    for(i=1;i<n;i++)
    {
        p = (BTree *)malloc(sizeof(BTree));
        p->data = a[i];
        p->left = p->right =NULL;
        cu = root;
 
        while(cu)
        {
            pa = cu;
            if(cu->data > p->data)
                cu = cu->left;
            else
                cu = cu->right;
        }
        if(pa->data > p->data)
            pa->left = p;
        else
            pa->right = p;
    }
 
    return root;
}

8

/  \

6  10

/  \  /  \

5  7  9  11

#include "stdio.h"
#include "stdlib.h"
 
int isPostorderResult(int a[],int n);
int helper(int a[],int s,int e);
 
int main(void)
{
  int a[7] = {5,7,6,9,11,10,8};
  int b[4] = {7,4,6,5};
  int tmp;
 
  tmp = isPostorderResult(a,7);
  printf("%d",tmp);
 
  return 0;
}
 
 
 
int isPostorderResult(int a[],int n)
{
  return helper(a,0,n-1);
}
 
int helper(int a[],int s,int e)
{
  int i,j,root;
   
  if(s == e)
    return 1; 
 
  for(i=0;i<e && a[i]<a[e];i++);
  if(i != 0 && helper(a,s,i-1) == 0)
    return 0;
 
  for(j=i;j<e && a[j]>a[e];j++);
  if(j==e && helper(a,i,j-1) == 1)
    return 1;
  else
    return 0;
   
   
}

8
/ \
6 10
/\ /\
5 7 9 11

    8
  /     \
  10     6
  /\       /\
11   9   7   5

#include "stdio.h"
#include "stdlib.h"
 
#define MAXSIZE 8
 
typedef struct node
{
  int data;
  struct node * left;
  struct node * right;
}BTree;
 
void swap(BTree ** x,BTree ** y);//交换左右孩子
void mirror(BTree * root);//递归实现函数声明
void mirrorIteratively(BTree * root);//非递归实现函数声明
BTree * CreatTree(int a[],int n);//创建二叉树（产生二叉排序树）
void Iorder(BTree * root);//中序遍历查看结果
 
int main(void)
{
  int array[MAXSIZE] = {5,3,8,7,2,4,1,9};
  BTree * root;
 
  root = CreatTree(array,MAXSIZE);
 
  printf("变换前：\n");
  Iorder(root);
 
  printf("\n变换后：\n");//两次变换，与变化前一致
  mirror(root);
  mirrorIteratively(root);
  Iorder(root);
 
 
 
  printf("\n");
 
  return 0;
}
 
void swap(BTree ** x,BTree ** y)
{
  BTree * t = * x;
  * x = * y;
  * y = t;
}
 
void mirror(BTree * root)
{
  if(root == NULL)//结束条件
    return;
   
  swap(&(root->left),&(root->right));//交换
  mirror(root->left);//左子树递归
  mirror(root->right);//右子树递归
}
 
void mirrorIteratively(BTree * root)
{
  int top = 0;
  BTree * t;
  BTree * stack[MAXSIZE+1];
   
  if(root == NULL)
    return;
 
  //手动压栈、弹栈
  stack[top++] = root;
  while(top != 0)
  {
    t = stack[--top];   
    swap(&(t->left),&(t->right));
 
    if(t->left != NULL)
      stack[top++] = t->left;
    if(t->right != NULL)
      stack[top++] = t->right;
  }
}
 
//产生二叉排序树
BTree * CreatTree(int a[],int n)
{
  BTree * root ,*p,*cu,*pa;
  int i;
   
  root = (BTree *)malloc(sizeof(BTree));
  root->data = a[0]; 
  root->left = root->right =NULL;
 
  for(i=1;i<n;i++)
  {
    p = (BTree *)malloc(sizeof(BTree));
    p->data = a[i];
    p->left = p->right =NULL;
    cu = root;
 
    while(cu)
    {
      pa = cu;
      if(cu->data > p->data)
        cu = cu->left;
      else
        cu = cu->right;
    }
    if(pa->data > p->data)
      pa->left = p;
    else
      pa->right = p;
  }  
 
  return root;
}
//中序遍历
void Iorder(BTree * root)
{
  if(root)
  {    
    Iorder(root->left);
    printf("%3d",root->data);
    Iorder(root->right);
  }
}