如下

#include<bits/stdc++.h>
using namespace std ;

const int maxn = 1e8 + 5 ;

int n ;
int a[maxn] ;
int b[maxn] ;
int flag ;

int main()
{
	cin >> n ;
	cin >> a[1] ;
	b[1] = a[1] ;
	for( int i = 2 ; i <= n ; i++ )
		{
			cin >> a[i] ;
			b[i] = 	abs( a[i] - a[i - 1] ) ;
		}
	for( int i = 1 ; i <= n ; i++ )
		{
			for( int j = 1 ; j <= n ; j++ )
				if( b[j] == i )
					{
						flag++ ;
						break ;
					}
		}
	if( flag == n - 1 )
		cout << "Jolly" << "\n" ;
	else
		cout << "Not jolly" << "\n" ;
}

不知有么有佬来优化一波，上面是AC代码