Question $2$: Problem Statement:

Given an array of integers, a$,$ return the maximum difference of any pair of numbers such that the larger integer in the pair occurs at a higher index $($in the array$)$ than the smaller integer.

Return $-1$ if you cannot find a pair that satisfies this condition.

Constraints: $1N1,000,000$

$-1,000,000a[i]1,000,000$AAiin$[0,N-1]$

Input Format: The first line of the input is $N($the number of elements in the array$),$ and then followed by $N$ elements each in a separate line.

Sample Input $0$:

$7$

$2$

$3$

$10$

$2$

$4$

$8$

$1$

SampleOutput $0$:

$8$

Explanation $0$:

For the array $\{2,3,10,2,4,8,1\}$ given above, $10$ is the largest number in the array and $1$ is the smallest number in the array. However, the index of $10$ is lower than the lowest index that contains a $1$ so the condition of the problem is not satisfied. Using zero$-$based index notation, the correct answer is $a[2]-a[0]=10-2=8.$ This satisfies the condition that the larger number in the pair should be positioned at a higher index in the array than the smaller number.

Sample Input $1$:$795632$

SampleOutput $1$:

$2$

Explanation $1$: The value of maxDifference is $9-7=2.$

$9$ occurs at a$[1]$ and $7$ occurs at a$[0].$ This satisfies the condition that the larger number must have a higher index than the smaller number.

Please write code in Java.