Print Common Nodes in Two Binary Search Trees ( intersection of two BSTs )

PROBLEM :

Given two Binary Search Trees, find common nodes in them. In other words, find intersection of two BSTs.

Example:

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SIMPLE c++ IMPLEMENTATION :
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/*
typedef struct BST
{
int info ;
struct BST *left ;
struct BST *right ;
}tree ;                                 */

int size_tree(tree* root) ;
void inorder_array_fill(tree* ,int [],int *) ;

void check_intersection_2BST(tree *root1,tree *root2)
{
int s1,s2 ;
s1=size_tree(root1) ;
s2=size_tree(root2) ;

int array1[s1],array2[s2],i ;
i=0 ;
inorder_array_fill(root1,array1,&i) ;
i=0 ;
inorder_array_fill(root2,array2,&i) ;

int a,b ;
a=0;
b=0 ;

while(a!=s1&&b!=s2)
{
if(array1[a]==array2[b])
{
cout<<array1[a]<<" " ;
a++ ;
b++ ;
}
else if(array1[a]>array2[b])
b++ ;
else
a++ ;
}
}

int size_tree(tree* root)
{
if(root==NULL)
return 0 ;

return ((size_tree(root->left))+(size_tree(root->right))+1) ;
}

void inorder_array_fill(tree* root,int a[],int *s)
{
    if(root==NULL)
        return  ;
     
    inorder_array_fill(root->left,a,&(*s)) ;
    a[(*s)++]=root->info ;
    inorder_array_fill(root->right,a,&(*s)) ;
 
}

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