Write a method union$($int$[]$ a$,$ int$[]$ b$)$ that returns an array that is the union of the elements in the two arrays. You may assume that the input arrays a and b are always given as sorted arrays $($increasing order$).$ The union of the elements is all of the elements from both arrays without any duplicates. The resulting array should also be in sorted order. Examples: Input: a $=\{1,1,2,2,2,4\},$ b $=\{2,2,4,4\}$ Output: $\{1,2,4\}$ Input: a $=\{3,5,10,10,10,15,15,20\},$ b $=\{5,10,10,15,30\}$ Output: $\{3,5,10,15,20,30\}$