Problem 2172. Delete the rows in the middle

We will delete the rows in the middle and keep the first and the last rows.

For example if input is

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.

Solve

Last solution submitted on Aug 09, 2019

Jon on 25 Mar 2014

The description of this problem is not very clear. It's really asking for the first and last row for each unique value in the first column.

rifat on 11 Jun 2014

"However there will be more than one row index and that makes this question challenging." - that really explains nothing to me