#include <iostream>
using namespace std;
struct node{
node *l,*r; int k;
};
void alter_wrong(node *x){x=NULL;}
void alter_correct(node **x){*x=NULL;}
int main(){
node *root=new node;
alter_wrong(root);
cout<<(root==NULL)<<endl;
alter_correct(&root);
cout<<(root==NULL)<<endl;
return 0;
}
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