1.0 KiB
1.0 KiB
How the fast iterator works
Consider the following example, where we have 6
iterators, sorted from
left to right in ascending order.
Our 'primary' A
iterator is on the left, containing the elements [0,1,8]
A B C D E F
0 1 2 4 7 9
1 2 9 - 14 13
8 8 - 15 15
- - - 16
-
When we call Next
on the primary iterator, we get (ignoring the future keys)
A B C D E F
1 1 2 4 7 9
We detect that we now got an equality between our element and the next element.
And we need to continue Next
ing on the next element
1 2 2 4 7 9
And move on:
A B C D E F
1 2 9 4 7 9
Now we broke out of the equality, but we need to re-sort the element C
A B D E F C
1 2 4 7 9 9
And after shifting it rightwards, we check equality again, and find C == F
, and thus
call Next
on C
A B D E F C
1 2 4 7 9 -
At this point, C
was exhausted, and is removed
A B D E F
1 2 4 7 9
And we're done with this step.