问题描述:
按先序遍历的扩展序列建立二叉树的二叉链表存储结构,实现二叉树先序、中序、后序遍历的递归算法,实现二叉树中序遍历的非递归算法,实现二叉树层次遍历的非递归算法,求二叉树的结点个数,求二叉树的深度。
代码实现:
#include <stdio.h>
#include <stdlib.h>
#define MSIZE 100
typedef struct Node{
char data;
struct Node *lchild;
struct Node *rchild;
}Node, *Tree;
//定义一个二叉树
void CreatTree(Tree *T){
char ch;
scanf("%c",&ch);
if(ch == ' ')
(*T) = NULL;
else
{
(*T) = (Tree)malloc(sizeof(Node));
(*T)->data = ch;
CreatTree(&((*T)->lchild));
CreatTree(&((*T)->rchild));
}
}
//读入用户输入生成一个二叉树
void Front(Tree T){
if(T)
{
printf("%c", T->data);
Front(T->lchild);
Front(T->rchild);
}
}
//先序遍历的递归实现
void Middle(Tree T){
if(T)
{
Middle(T->lchild);
printf("%c", T->data);
Middle(T->rchild);
}
}
//中序遍历的递归实现
void Last(Tree T){
if(T)
{
Last(T->lchild);
Last(T->rchild);
printf("%c", T->data);
}
}
//后序遍历的递归实现
void Middle2(Tree T){
Node *stack[MSIZE];//定义一个栈
int top = -1;
Node *p;//定义一个临时指针p
p = T;
while(p || top > -1)
{
if(p)
{
top++;
stack[top] = p;
p = p->lchild;//p不为空,遍历左子树
}
else
{
p = stack[top];
printf("%c", p->data);
top--;
p = p->rchild;//遍历右子树
}
}
}
//利用栈实现非递归中序遍历
void level(Tree T){
Node *queue[MSIZE];//定义队列
int front = 0;
int rear = 0;
int count;
Node *p;//定义临时指针p
rear++;
queue[rear] = T;//根节点进入队列
while(front != rear)//队列不空
{
count = rear - front;
while(count > 0)
{
count--;
front++;
p = queue[front];
printf("%c", p->data);
if(p->lchild)
{
rear++;
queue[rear] = p->lchild;
}
if(p->rchild)
{
rear++;
queue[rear] = p->rchild;
}
}
}
}
//二叉树的层次遍历
int NodeCount(Tree T){
if(!T)
return 0;
else
return (NodeCount(T->lchild) + NodeCount(T->rchild) + 1);
}
int TreeDepth(Tree T){
int a, b;
if(!T)
return 0;
else
{
a = TreeDepth(T->lchild);
b = TreeDepth(T->rchild);
if(a > b)
return (a + 1);
else
return (b + 1);
}
}
int main() {
Tree T = NULL;
printf("请输入数的先序扩展序列,输入空格表示该位置是空,按回车结束\n");
CreatTree(&T);//生成树
printf("前序遍历:");
Front(T);
printf("\n");
printf("中序遍历:");
Middle(T);
printf("\n");
printf("后序遍历:");
Last(T);
printf("\n");
printf("非递归中序遍历:");
Middle2(T);
printf("\n");
printf("非递归层次遍历:");
level(T);
printf("\n");
printf("树的结点个数为:%d\n", NodeCount(T));
printf("树的深度为:%d\n", TreeDepth(T));
system("pause");
}