Design an iterator class ZigzagIterator that takes two integer arrays v1 and v2 and iterates through their elements by alternating between the arrays.

The iterator must support the following methods:

• next() returns the next integer in the alternating traversal.

• hasNext() returns true if there is at least one remaining element to return, otherwise returns false.

When one of the arrays runs out of elements, the iterator should continue returning the remaining elements from the other array in order.

Note: For the follow up, if more than two arrays are provided, interpret the order as cyclic across the arrays, skipping any array that has no remaining elements.

Constraints:

• $0 \leq$ v1.length, v2.length $\leq 1000$

• $1 \leq$ v1.length $+$ v2.length $\leq 2000$

• $-2^{31} \leq$ v1[i], v2[i] $\leq 2^{31} - 1$

Input: v1 = [10, 20, 30]-List[int], v2 = [1, 2, 3]-List[int]
Output: [10, 1, 20, 2, 30, 3]-List[int]
Explanation: The iterator alternates between v1 and v2 until both are exhausted, taking 10 (v1), 1 (v2), 20 (v1), 2 (v2), and so on.

Input: v1 = [7, 8, 9, 10, 11]-List[int], v2 = [100]-List[int]
Output: [7, 100, 8, 9, 10, 11]-List[int]
Explanation: It alternates while possible, taking 7 (v1) and 100 (v2). Then v2 is exhausted, so the iterator continues returning the remaining elements from v1 in order.

Input: v1 = []-List[int], v2 = [-5, -4, -3, -2]-List[int]
Output: [-5, -4, -3, -2]-List[int]
Explanation: Since v1 is empty, the iterator returns all elements from v2 sequentially.

Input: v1 = [1, 2, 3]-List[int], v2 = [4, 5, 6, 7]-List[int], v3 = [8, 9]-List[int]
Output: [1, 4, 8, 2, 5, 9, 3, 6, 7]-List[int]
Explanation: For the follow-up with k vectors in cyclic order, iterate across the vectors (v1 → v2 → v3 → v1 → ...), skipping any vector with no remaining elements. After v3 runs out, continue cycling between the remaining vectors until all are exhausted.

Now, let’s take a moment to make sure you’ve correctly understood the problem. The quiz below helps you check if you’re solving the correct problem:

We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.

Implement your solution in the following coding playground.