自己写了个查找最大值和最小值的代码，不知道为什么没有输出，求大佬调QAQ

代码如下：

#include<bits/stdc++.h>
#define int long long
using namespace std;
int n;
struct Node {
	int data;
	Node *l;
	Node *r;
};
Node *root;

Node *build(int data , Node *root) {
	if(root == NULL) {
		Node *newnode = new Node;
		newnode -> data = data;
		newnode -> l = NULL;
		newnode -> r = NULL;
		root = newnode;
		return root;
	}
	if(root -> data < data)
		root -> r = build(data , root -> r);
	if(root -> data > data)
		root -> l = build(data , root -> l);
	return root;
}

void find1(Node *root) {
	while(root -> l != NULL)
		root = root -> l;
	cout << root -> data << '\n';
	return;
}

void find2(Node *root) {
	while(root -> r != NULL)
		root = root -> r;
	cout << root -> data << '\n';
	return;
}

signed main() {
	cin >> n;
	root = new Node;
	root = NULL;
	for(int i = 1;i <= n;i ++) {
		int x;
		cin >> x;
		build(x , root);
	}
	find1(root);
	find2(root);
	return 0;
}