4.3.cpp

#include <iostream>
#include <cstring>
#include <cmath>
using namespace std;

const int maxn = 100;
struct Node{
    int key;
    Node *lchild, *rchild, *parent;
};
Node *p, node[maxn];
int cnt;

void init(){
    p = NULL;
    memset(node, '\0', sizeof(node));
    cnt = 0;
}
void create_minimal_tree(Node* &head, Node *parent, int a[], int start, int end){
    if(start <= end){
        int mid = (start + end)>>1;
        node[cnt].key = a[mid];
        node[cnt].parent = parent;
        head = &node[cnt++];
        create_minimal_tree(head->lchild, head, a, start, mid-1);
        create_minimal_tree(head->rchild, head, a, mid+1, end);
    }
}
int height(Node *head){
    if(head == NULL) return 0;
    return max(height(head->lchild), height(head->rchild)) + 1;
}
int main(){
    init();
    int a[] = {
        0, 1, 2, 3, 4, 5, 6, 7, 8
    };
    Node *head = NULL;
    create_minimal_tree(head, NULL, a, 0, 8);
    cout<<height(head)<<endl;
    return 0;
}