Code câu 1

#include <iostream>
using namespace std;
struct Node
{
    int x;
    Node *pLeft, *pRight;
};

typedef Node * Tree;
void Count_la(Tree T, int &dem)
{
    if (T != NULL)
    {
        if (T->pLeft == NULL && T->pRight == NULL) dem++;
        Count_la(T->pLeft, dem);
        Count_la(T->pRight, dem);
    }
}
Node * Search_node(Tree T, int key)
{
    if (T != NULL)
    {
        if (T->x == key) return  T;
        if (T->x > key) return Search_node(T->pLeft, key);
        else return Search_node(T->pRight, key);
    }
    return NULL;
}