Given three arrays sorted in increasing order. Find the elements that are common in all three arrays.
Note: can you take care of the duplicates without using any additional Data Structure?
Example 1:
Input:
n1 = 6; A = {1, 5, 10, 20, 40, 80}
n2 = 5; B = {6, 7, 20, 80, 100}
n3 = 8; C = {3, 4, 15, 20, 30, 70, 80, 120}
Output: 20 80
Explanation: 20 and 80 are the only
common elements in A, B and C.

Your Task:
You don't need to read input or print anything. Your task is to complete the function commonElements() which take the 3 arrays A[], B[], C[] and their respective sizes n1, n2 and n3 as inputs and returns an array containing the common element present in all the 3 arrays in sorted order.
If there are no such elements return an empty array. In this case the output will be printed as -1.

Expected Time Complexity: O(n1 + n2 + n3)
Expected Auxiliary Space: O(n1 + n2 + n3)

Constraints:
1 <= n1, n2, n3 <= 10^5
The array elements can be both positive or negative integers.

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