1.15

third.erl

-module(third).
-export([x0r1/2, x0r2/2, x0r3/2, maxThree/3, howManyEqual/3]).

x0r1(A,B) ->
  A =/= B.

x0r2(A,B) ->
  not (A == B).

x0r3(A,B) ->
  ((not A and B) or (A and not B)).

maxThree(X,Y,Z) ->
  max(max(X,Y),Z).

howManyEqual(X,X,X) -> 3;
% if the last argument was same, that should matched above.
howManyEqual(X,X,_) -> 2;
howManyEqual(X,_,X) -> 2;
howManyEqual(_,X,X) -> 2;
howManyEqual(_,_,_) -> 0.