// Program for Jolly Jumper Sequence
import java.util.*;
class GFG
{
// Function to check whether given sequence
// is Jolly Jumper or not
static boolean isJolly(int a[], int n)
{
// Boolean vector to diffSet set of differences.
// The vector is initialized as false.
boolean []diffSet = new boolean[n];
// Traverse all array elements
for (int i = 0; i < n - 1 ; i++)
{
// Find absolute difference
// between current two
int d = Math.abs(a[i] - a[i + 1]);
// If difference is out of range or repeated,
// return false.
if (d == 0 || d > n - 1 ||
diffSet[d] == true)
return false;
// Set presence of d in set.
diffSet[d] = true;
}
return true;
}
// Driver Code
public static void main(String[] args)
{
int a[] = {11, 7, 4, 2, 1, 6};
int n = a.length;
if(isJolly(a, n))
System.out.println("Yes");
else
System.out.println("No");
}
}
// This code is contributed by Rajput-Ji