Problem 1915. GJam 2013 Veterans: Baby Height Prediction

This Challenge is derived from GJam 2013 Veterans Baby Height. Only the first 82 of 5958 test cases are evaluated.

The GJam story goes that a baby's final height can be bounded given its mom's and dad's height(Ht) and its sex. Baby Nominal Ht is (Mom Ht+ Dad Ht + Baby Sex Adj)/2. A boy gets an Adjust of +5" while a girl is -5". The range is +/- 4" from nominal. However, for fractional inches the range is reduced until endpoints are whole inches.

Input: str , String of Sex, Mom and Dad Height x'y"

Output: H , string of Predicted Height Range

Examples: [str] [H]

B 5'11" 6'2"  spawns 5'11" to 6'7"
G 5'11" 6'2" spawns 5'6" to 6'2"
B 3'4" 3'4" spawns 3'3" to 3'10"

Commentary:

1) Provide input like fgetl per test case
2) 15 of 32 entrants completed this Challenge
3) This is a test of regexp and sprintf formatting (or just regexprep)