PAT A1099 Build A Binary Search Tree

#include<cstdio> 
#include<vector>
#include<queue>
#include<algorithm>
using namespace std;
const int maxn = 110;
int n;
struct node{
	int data;
	int lchild;
	int rchild;
}Node[maxn];
int ori[maxn];
int index = 0;

void inOrder(int root){
	if(root == -1)  return;
	inOrder(Node[root].lchild);
	Node[root].data = ori[index++];
	inOrder(Node[root].rchild);
}

int num = 0;
void BFS(int root){
	queue<int> q;
	q.push(root);
	while(! q.empty()){
		int newnode = q.front();
		q.pop(); num++;
		printf("%d",Node[newnode].data);
		if(num != n) printf(" ");
		if (Node[newnode].lchild != -1) q.push(Node[newnode].lchild);
		if (Node[newnode].rchild != -1) q.push(Node[newnode].rchild);
	}
}

int main(){
	scanf("%d",&n);
	int lchild,rchild;
	for(int i = 0; i < n ; i++){
		scanf("%d %d",&lchild,&rchild);
		Node[i].lchild = lchild;
		Node[i].rchild = rchild;
	}
	for(int i = 0; i < n; i++){
		scanf("%d",&ori[i]);
	}
	sort(ori, ori+n);
	inOrder(0);
	BFS(0);
	return 0;
}