Problem 2264. GJam 2011 Africa Qualifier C: House, maximum area rectangle

This Challenge is derived from GJam 2011 Africa: Building a House. Google Code Jam 2014 Kicks Off its Qualifier round April 11. GJam Registration. The Test Suite, at the bottom, contains a full GJam file input read (fgetl, string), process, and Output example.

Determine maximum area rectangular House that can be placed on a plot given a text terrain map of G-Grass,S-Shrubs,R-Rock,W-Water, and T-Tree. The house can not be placed over Water, Trees, or Rocks. Square is a special rectangle.

Input: M, Text Array of GWRST

Output: A, maximum House area that can be placed

Example:

GGTGG  A=9
TGGGG
GSSGT
GGGGT
GWGGG
RGTRT
RTGWT
WTWGR

Additional GJam solutions can be found at Example GJam Matlab solutions. Select Find Solutions, change Language to Matlab. There were only 50 Qualifier Matlab entrants in 2013 and a mere 2 Matlab users achieved round 2.