PAT甲级1043

#include<iostream>
#include<vector>
using namespace std;

vector<int> res;
struct Node{
	int key;
	struct Node* l;
	struct Node* r;
};

int mid;
int isBST(vector<int> a, int root){
	for (int i = 1; i < a.size(); i++){
		if (root <= a[i]){
			mid = i;
			break;
		}
	}
	int temp = a.size() - 1;
	while (temp != mid - 1){
		if (a[temp] < root){
			return 0;
		}
		temp--;
	}
	while (temp != 0){
		if (a[temp] >= root){
			return 0;
		}
		temp--;
	}
	return 1;
}

int isMirror(vector<int> a, int root){
	for (int i = 1; i < a.size(); i++){
		if (root > a[i]){
			mid = i;
			break;
		}
	}
	int temp = a.size() - 1;
	while (temp != mid - 1){
		if (a[temp] >= root){
			return 0;
		}
		temp--;
	}
	while (temp != 0){
		if (a[temp] < root){
			return 0;
		}
		temp--;
	}
	return 1;
}

void insertNode1(Node* t, int key){
	Node *head, *parent;
	Node *p = new Node;
	p->key = key;
	p->l = p->r = NULL;
	
	head = t;
	while (head){
		parent = head;
		if (key < head->key) head = head->l;
		else head = head->r;
	}
	if (key < parent->key) parent->l = p;
	else parent->r = p;
}

void insertNode2(Node* t, int key){
	Node *head, *parent;
	Node *p = new Node;
	p->key = key;
	p->l = p->r = NULL;
	
	head = t;
	while (head){
		parent = head;
		if (key >= head->key) head = head->l;
		else head = head->r;
	}
	if (key >= parent->key) parent->l = p;
	else parent->r = p;
}

void creat1(Node* t, vector<int> a, int length){
	for (int i = 1; i < length; i++){
		insertNode1(t, a[i]);
	}
}

void creat2(Node* t, vector<int> a, int length){
	for (int i = 1; i < length; i++){
		insertNode2(t, a[i]);
	}
}

void fun(Node *t){
	if(t){
		fun(t->l);
		fun(t->r);
		res.push_back(t->key);
	}
}

int main(){
	vector<int> a;
	int n, m;
	cin >> n;
	for (int i = 0; i < n; i++){
		cin >> m;
		a.push_back(m);
	}
	int root = a[0];
	if (isBST(a, root) == 0 && isMirror(a, root) == 0){
		cout << "NO";
		return 0;
	}
	if (isBST(a, root) == 1){
		cout << "YES" << endl;
		Node *t = new Node;
		t->key = a[0];
		t->l = t->r = NULL;
		creat1(t, a, a.size());
		fun(t);
		for (int i = 0; i < res.size(); i++){
			if (i != res.size() - 1){
				cout << res[i] << " ";
			}
			else cout << res[i];
		}
		return 0;
	}
	if (isMirror(a, root) == 1){
		cout << "YES" << endl;
		Node *t = new Node;
		t->key = a[0];
		t->l = t->r = NULL;
		creat2(t, a, a.size());
		fun(t);
		for (int i = 0; i < res.size(); i++){
			if (i != res.size() - 1){
				cout << res[i] << " ";
			}
			else cout << res[i];
		}
		return 0;
	}
}