You get an array of arrays.
If you sort the arrays by their length, you will see, that their length-values are consecutive.
But one array is missing!
You have to write a method, that return the length of the missing array.
Example:
[[1, 2], [4, 5, 1, 1], [1], [5, 6, 7, 8, 9]] --> 3
If the array of arrays is null/nil or empty, the method should return 0.
When an array in the array is null or empty, the method should return 0 too!
There will always be a missing element and its length will be always between the given arrays.