前序、前中、中后序生成二叉树

中序后序生成树

bitree In_rear_creatTree(char rear[],int rstart,int rend,char in[],int istart,int iend){
//后中双遍历创造树

	if(rstart > rend)
		return NULL;

	bitree t = new bitTree();
	char ch  = rear[rend]; //获得根结点 后序遍历的根结点在尾部

	t->val = ch; //赋值

	int i = 0;

	while(in[i] != ch)i++;

	//根据根结点在中序遍历中找到分界点
	t->left  = In_rear_creatTree(rear,rstart,rstart+i-istart-1,in,istart,i-1);
	t->right = In_rear_creatTree(rear,rstart+i-istart,rend-1,in,i+1,iend); 

	return t;

}

bitree preInitTree(){ //前序生成此树

	bitree t;
	
	char ch;
	ch = getchar();

	if(ch == '@') return NULL;   //符号@代表改结点为null 

	t = new bitTree();
	t->val = ch;
	
	t->left = preInitTree();
	t->right = preInitTree();

	return t;
} 

bitree pre_In_creatTree(char pre[],int pstart,int pend,char in[],int istart,int iend){ 
//前中双遍历创造树

	
	if(pstart > pend)
		return NULL;

	bitree t = new bitTree();
	char ch = pre[pstart]; //获得根结点  前序遍历的根结点在头部

	t->val = ch; //赋值

	int i = 0;

	while(in[i] != ch)i++;

	//根据根结点在中序遍历中找到分界点
	t->left  = pre_In_creatTree(pre,pstart+1,pstart+i-istart,in,istart,i-1);
	t->right = pre_In_creatTree(pre,pstart+i-istart+1,pend,in,i+1,iend); 

	return t;
}

标签：pre,ch,istart,前中,前序,char,int,二叉树,rear
来源： https://blog.csdn.net/weixin_46258925/article/details/110588340