Q3 [10 points][Stacks] Part 1 [7 points] Write a method called constructStack to be considered outside the Arraystack class and has three parameters s,1s2 and s3 of type Arraystack. The method fills s3 stack by making the top of s3 as the bottom of s1 and the bottom of s3 as the top of s1. The rest (remaining) of the elements of s3 stack will be the same as those in s2 with the same order. Assume s1 and s2 are not empty and s3 is empty. Assume that ArrayStack class methods are accessible to you. The method head is pablic statie > void constructStack(ArrayStack s1, ArrayStack s2, AmayStack 83 ) 53: After method call: top668990 Part2 [3 points] Evaluate the following postfix expression using stacks, show the steps step by step