You are ignoring the overlapse. For example the ex.1 Has 1-5 and 1-5. if you were to write every number between the both of them you would indeed get 9 numbers(length 8), but all of them would be dublicated. So the number of the unique numbers is 5(and the length is 4): 1, 2, 3, 4, 5; it is simpler to understand if you write the intervals on one line in a pice of paper. :)

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upper bound is excluded in the inputs, so:

n:      1   5    ...
1-5:    ----
1-6:    -----
5-11:       ------
10-20:           ----------
16-19:                 ---
merged: ------------------- <=> from 1 to 19 (included), hence 19

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What do i do wrong? Golang

Refer to the kata's description.

Hi. =) U're rgiht. That may happen, I am chiting some times. This cata was needed only for my course passing

Array a:       6, 9, 7, 0, 11,
Array b:   -2,       7,        18, -1, 16, -19, 3, -18, -5,
Answer:        6, 9,    0, 11,