add an abstract class for the two algorithms  On branch ch15 	modified:   ch15/cut_rod.hpp
add an abstract class for the two algorithms
 On branch ch15
	modified:   ch15/cut_rod.hpp

tushar2708/CLRS,tushar2708/CLRS,tushar2708/CLRS,Mooophy/CLRS,opensourceDA/CLRS,opensourceDA/CLRS,Mooophy/CLRS,Mooophy/CLRS,opensourceDA/CLRS,Mooophy/CLRS,tushar2708/CLRS,opensourceDA/CLRS