Given the interface `IntIterator`

defined in the following, implement the method `isDistanceZeroOrOne(IntIterator a, IntIterator b)`

to return if the distance between `a`

and `b`

is at most one, where the distance is defined as the minimum number of modifications to make them equal to each other. Modifications can be: 1) change an int in `a`

. 2) insert an int to `a`

. 3) remove an int from `a`

. For example, the method should return `true`

for 1, 2, 2 and 1, 3, 2, 2.