PAT-A1020(C/C++代码解析)

注：BFS，重构二叉树

#include 
#include 
#include 
#include 
using namespace std;
const int maxn=88;
int post[maxn],pre[maxn],in[maxn];

struct node{
	int data;
	node* lchild;
	node* rchild;
};

node* create (int postL,int postR,int inL,int inR)
{
	if (postL>postR)
	return NULL;
	
	node* root=new node;
	root->data=post[postR];
	
	int k;
	for (k=inL;k<=inR;k++)
	if (post[postR]==in[k])
	break;
	
	int numLeft=k-inL;
	
	root->lchild=create(postL,postL+numLeft-1,inL,k-1);
	
	root->rchild=create(postL+numLeft,postR-1,k+1,inR);
	
	
	return root;
} 

int num=0,n;
void BFS(node* root)
{
	queue q;
	q.push(root);
	while (q.empty()==false)
	{
		node* now=q.front();
		q.pop();
		printf ("%d",now->data);
		num++;
		if (numlchild!=NULL)
		q.push(now->lchild);
		if (now->rchild!=NULL)
		q.push(now->rchild);
	}
}

int main ()
{
	int i;
	scanf ("%d",&n);
	for (i=0;i