24번

#include<iostream>
#include<vector>
#include<stdlib.h>
using namespace std;
int main() {
	int sum = 0;
	int N = 0;
	cin >> N;
	vector<int> arr(N);
	vector<int> arr2(N-1);
	for (int i = 0; i < N; i++)
	{
		cin >> arr[i];
		
	}
	for (int i = 0; i < N-1; i++)
	{
		arr2[i] = i+1;
	}
	for (int i = 0; i < N-1; i++)
	{
		for (int j = 0; j < N-1; j++)
		{
			if (arr2[j] == abs(arr[i + 1] - arr[i]))
			{
				arr2[j] = 0;
			}
		}
	}
	for (int i = 0; i < N-1; i++)
	{
		sum = arr2[i] + sum;
	
	}
	if (sum != 0)
	{
		cout << "NO";
	}
	else if (sum == 0)
	{
		cout << "YES";
	}

}