二叉树

二叉树的简单操作:

//可以输入ABC##DE#G##F###
#include<stdio.h>
#include<malloc.h>
#include<stdlib.h>
#define MAX 20
typedef struct BTNode{       /*节点结构声明*/
	char data ;               /*节点数据*/
	struct BTNode *lchild;
	struct BTNode *rchild ;  /*指针*/
}*BiTree;

void createBiTree(BiTree *t){ /* 先序遍历创建二叉树*/
	char s;
	BiTree q;
	printf("\nplease input data:(exit for #)");
	s=getchar();
	if(s=='#'){*t=NULL; return;}
	q=(BiTree)malloc(sizeof(struct BTNode));
	if(q==NULL){printf("Memory alloc failure!"); exit(0);}
	q->data=s;
	*t=q;
	createBiTree(&q->lchild); /*递归建立左子树*/
	createBiTree(&q->rchild); /*递归建立右子树*/
}

void PreOrder(BiTree p){  /* 先序遍历二叉树*/
    if ( p!= NULL ) {
       	printf("%c", p->data);
       	PreOrder( p->lchild ) ;
       	PreOrder( p->rchild) ;
    }
}
void InOrder(BiTree p){  /* 中序遍历二叉树*/
    if( p!= NULL ) {
 	 InOrder( p->lchild ) ;
   	 printf("%c", p->data);
   	 InOrder( p->rchild) ;
    }
}
void PostOrder(BiTree p){  /* 后序遍历二叉树*/
   if ( p!= NULL ) {
    	PostOrder( p->lchild ) ;
       	PostOrder( p->rchild) ;
       	printf("%c", p->data);
    }
}

void Preorder_n(BiTree p){ /*先序遍历的非递归算法*/
    BiTree stack[MAX],q;
    int top=0,i;
    for(i=0;i<MAX;i++) stack[i]=NULL;/*初始化栈*/
    q=p;
    while(q!=NULL){
        printf("%c",q->data);
        if(q->rchild!=NULL) stack[top++]=q->rchild;
        if(q->lchild!=NULL) q=q->lchild;
        else
            if(top>0) q=stack[--top];
            else q=NULL;
    }
}

void release(BiTree t){ /*释放二叉树空间*/
  	if(t!=NULL){
    	release(t->lchild);
    	release(t->rchild);
    	free(t);
  	}
}
int Depth(BiTree t)
{
	int m,n;
	if(t==NULL) return 0;
	else
	{
		m=Depth(t->lchild);
		n=Depth(t->rchild);
		if(m>n) return(m+1);
		else return(n+1);
	}
}
int NodeCount(BiTree t)
{
	if(t==NULL)
        return 0;
	else
        return NodeCount(t->lchild)+NodeCount(t->rchild)+1;
}
int leaf_num(BiTree t)
{
    if (t == NULL)
        return 0;
    if (t->lchild == NULL && t->rchild == NULL)
        return 1;

    return (leaf_num(t->lchild) + leaf_num(t->rchild));
}

int main(){
    BiTree t=NULL;
    createBiTree(&t);
    printf("\n\n先序遍历二叉树为:");
    PreOrder(t);
    printf("\n\n中序遍历二叉树为:");
    InOrder(t);
    printf("\n\n后序遍历二叉树为:");
    PostOrder(t);
    printf("\n\n先序遍历序列（非递归）:");
    Preorder_n(t);
    printf("\n\n二叉树深度: ");
    printf("%d\n",Depth(t));
    printf("\n结点总数为: ");
    printf("%d\n",NodeCount(t));
    printf("\n叶子结点总数: ");
    printf("%d\n",leaf_num(t));
    release(t);
    return 0;
}

简单二叉树遍历:

比如这个

视频1 

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

struct node {
    int data;
    struct node *left;
    struct node *right;
};
typedef struct node Node;

void PreOrder(Node *node) { //先序
    if (node != NULL) {
        printf("%d\n", node -> data);
        PreOrder(node -> left);
        PreOrder(node -> right);
    }
}

void InOrder(Node *node) {//中序
    if (node != NULL) {
        InOrder(node -> left);
        printf("%d\n", node -> data);
        InOrder(node -> right);
    }
}

void PostOrder(Node *node) {//后序
    if (node != NULL) {
        PostOrder(node -> left);
        PostOrder(node -> right);
        printf("%d\n", node -> data);
    }
}

int main() {
    Node n1;
    Node n2;
    Node n3;
    Node n4;

    n1.data = 5;
    n2.data = 6;
    n3.data = 7;
    n4.data = 8;

    n1.left = &n2;
    n1.right = &n3;
    n2.left = &n4;
    n2.right = NULL;
    n3.left = NULL;
    n3.right = NULL;
    n4.left = NULL;
    n4.right = NULL;

    PreOrder(&n1);//先序
//    InOrder(&n1);//中序
//    PostOrder(&n1);//后序
    return 0;
}