# Algorithm

We have a series of input sources which could provide a sorted integer series. Please merge all of them and output a single sequence of integers which has been sorted:

The function to be implied should look like:

fn flat_sorted<T>(inps: impl ExactSizeIterator<Item=T>) -> impl Iterator<Item=u32>
where T: Iterator<Item= u32>

For example, we have 3 inputs whose output is `(1,3,5), (2,7), (4,6,8,9)` respectively, your output should be `(1,2,3,4,5,6,7,8,9)`

We also require at most *O(inps.len())^2* space for our implement