ACwing_1589. 构建二叉搜索树

ACwing_1589. 构建二叉搜索树

//
#include<bits/stdc++.h>
using namespace std;
#define T int							// T

const int N=111;
T xx[N],yy[N],in[N],ans[N];				// in[N]
int pos;

struct node
{
    T data;
    node *x,*y;
    node( T in=0,node *xx=NULL,node *yy=NULL ):data(in),x(xx),y(yy) {}
};

node* new_tree( int tt,node* &root )
{
    if( tt==-1 ) return root;			// tt==-1
    
    root=new node( tt );
    root->x=new_tree( xx[tt],root->x );
    root->y=new_tree( yy[tt],root->y );
    return root;
}

void dfs( node *root )
{
	if( root==NULL ) return ;			// return 
    dfs( root->x );
    root->data=in[pos++];
    dfs( root->y );
}

void DD( node *root )
{
    if( root==NULL ) return ;

    queue<node*> q; node *tt=NULL;
    q.push( root );
    
    while( !q.empty() )
    {
        tt=q.front(); q.pop();
        ans[pos++]=tt->data;			// tt
        if( tt->x ) q.push( tt->x );
        if( tt->y ) q.push( tt->y );
    }
}

void delete_tree( node *root )
{
    if( root==NULL ) return ;
    delete_tree( root->x );
    delete_tree( root->y );
    delete root;
}

int main()
{
    int n,i;
    while( cin>>n )
    {
        for( i=0;i<n;i++ ) cin>>xx[i]>>yy[i];
        for( i=0;i<n;i++ ) cin>>in[i];
        sort( in,in+n );				// sort

        node *root=NULL;
        new_tree( 0,root );
        
        pos=0; dfs( root );
        pos=0; DD( root );
        
        for( i=0;i<pos;i++ )
        {
            if( i ) cout<<" ";
            cout<<ans[i];
        }
        cout<<endl;

        delete_tree( root );
    }
    return 0;
}

"vs"

01 node *root

    root->x=new_tree( root->x );
    root->y=new_tree( root->y );

02 node* &root

    new_tree( root->x );
    new_tree( root->y );