Microsoft OA - SDE 2

Round 1

Questions:

1. Given an array with integers, find the maximum sum of any 2 numbers whose first and last digits match.
   E.g - [ 2, 36, 45, 306, 415] -> 36 + 306 < 45 + 415
   Ans - 460

2. Given a 2D matrix with 2 rows and N columns, containing only the characters 'R', 'W', '?', give the minimum replacements of '?' required to make the matrix balanced.
   The matrix would be balanced when it has equal number of 'W' and 'R' in all the rows and columns.
   E.g. - R1 - "WR???" ; R2 - "R???W" -> Balanced - R1 - "WR?WR" , R2 - "RW?RW" ; 4 replacements

Both questions had standard huge constraints.