We will delete the rows in the middle and keep the first and the last rows.
For example if input is
[1 2 1 7 1 8 1 6 1 5]
then output will be
[1 2 1 5]
keeping the first and the last rows. However there will be more than one row index and that makes this question challenging.
Note: Elements of input row index is always greater than or equal to 2.
Related Challenge - Problem 2084. Sum Rows