浙大PAT 1020. Tree Traversals (25)

#include<iostream>

#include<fstream>

#include<algorithm>

#include<vector>

#include<queue>

using namespace std;

//#define fin cin 

struct node

{
int value;
node *left,*right;
node(){value=0;left=right=NULL;}

};

node* maketree(int *post,int pstart,int pend,int *in,int instart,int inend)

{
if(pend<pstart||inend<instart)
return NULL;
else if(pstart==pend)
{
node *temp=new node;
temp->value=post[pend];
return temp;
}
else
{
int root=post[pend];
vector<int> lefttree;
int index1=instart;
while(in[index1]!=root)
{
lefttree.push_back(in[index1]);
index1++;
}
int index2=pstart;
while(find(lefttree.begin(),lefttree.end(),post[index2])!=lefttree.end())
{
index2++;
}
node *temp=new node;
temp->value=post[pend];
temp->left=maketree(post,pstart,index2-1,in,instart,index1-1);
temp->right=maketree(post,index2,pend-1,in,index1+1,inend);
return temp;
}

}

void printtree(node *tree) 
{
if(tree!=NULL)
{
cout<<tree->value<<endl;
printtree(tree->left);
printtree(tree->right);
}

}

void printtreelevel(queue<node> myqueue) 

{

if(myqueue.size()!=0)
{
node temp=myqueue.front();
cout<<" "<<temp.value;
if(temp.left!=NULL)
myqueue.push(*temp.left);
if(temp.right!=NULL)
myqueue.push(*temp.right);
myqueue.pop();
printtreelevel(myqueue);
}

}

int main()  

{  
/* ifstream fin("d:\in.txt" ); 
if (! fin.is_open())  
{ 
cout << "Error opening file";
system("pause");
exit (1); 
} */
int num;
cin>>num;
int *postorder=new int[num];
int *inorder=new int[num];
int *levelorder=new int[num];
for(int i=0;i<num;i++)
cin>>postorder[i];
for(int i=0;i<num;i++)
cin>>inorder[i];
node *tree=maketree(postorder,0,num-1,inorder,0,num-1);
//printtree(tree);
queue<node> myqueue;
cout<<tree->value;
if(tree->left!=NULL)
myqueue.push(*tree->left);
if(tree->right!=NULL)
myqueue.push(*tree->right);
printtreelevel( myqueue) ;

 

    system("PAUSE");  

    return 0;  

}