# Zig Zag Iterator

Zig Zag Iterator design

Given two 1d vectors, implement an iterator to return their elements alternately.

For example, given two 1d vectors:

v1 = [1, 2] v2 = [3, 4, 5, 6] By calling next repeatedly until hasNext returns false, the order of elements returned by next should be: [1, 3, 2, 4, 5, 6].

Follow up: What if you are given k 1d vectors? How well can your code be extended to such cases?

Zig Zag Iterator Solution

``````/**
* Your ZigzagIterator object will be instantiated and called as such:
* ZigzagIterator i = new ZigzagIterator(v1, v2);
* while (i.hasNext()) v[f()] = i.next();
*/

public class ZigZagIterator {
private Iterator<Integer> i;
private Iterator<Integer> j;
private Iterator<Integer> temp;

public ZigzagIterator(List<Integer> v1, List<Integer> v2) {
i = v1.iterator();
j = v2.iterator();
}

public int next() {
if(i.hasNext()) {
temp = i;
i = j;
j = temp;
}

return j.next();
}

public boolean hasNext() {
return i.hasNext() || j.hasNext();
}
}``````