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Курс във Факултета по Математика и Информатика към СУ

Решение на Трета задача от Йордан Стефанов

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Към профила на Йордан Стефанов

Резултати

  • 6 точки от тестове
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  • 6 точки общо
  • 13 успешни тест(а)
  • 0 неуспешни тест(а)

Код

class Expr
def self.build expression
if expression[0] == :number
Number.new expression[1]
elsif expression.size == 2
Unary.build expression
else
Binary.build expression
end
end
end
class Number < Expr
attr_reader :argument
def initialize argument
@argument = argument
end
def == expression
if not expression.is_a? Number
return false
end
@argument == expression.argument
end
def evaluate _ = {}
self.argument
end
def simplify
self
end
def + expression
if argument == 0
return expression
end
if expression.is_a? Number
return Number.new( argument + expression.argument)
end
return Addition.new self, expression
end
def * expression
if argument == 0
return Number.new 0
elsif argument == 1
return expression
end
if expression.is_a? Number
return Number.new( argument * expression.argument)
end
return Multiplication.new self, expression
end
def derive _
Number.new 0
end
end
class Unary < Expr
attr_reader :argument
def initialize argument
@argument = argument
end
def == expression
if not expression.class == self.class
return false
end
@argument == expression.argument
end
def + expression
if expression.is_a? Number and expression.evaluate == 0
return self
end
return Addition.new self, expression
end
def * expression
if expression.is_a? Number and expression.evaluate == 0
return Number.new 0
elsif expression.is_a? Number and expression.evaluate == 1
return self
end
return Multiplication.new self, expression
end
def self.build expression
case expression[0]
when :variable
Variable.new expression[1]
when :-
Negation.new Expr.build expression[1]
when :sin
Sine.new Expr.build expression[1]
when :cos
Cosine.new Expr.build expression[1]
end
end
end
class Variable < Unary
def evaluate context = {}
if not context.has_key? argument
raise "the context #{ context.inspect } does not contains the variable: #{ self.inspect }"
end
context[argument]
end
def simplify
self
end
def derive variable
if variable == argument
return Number.new 1
end
return Number.new 0
end
end
class Sine < Unary
def evaluate context = {}
Math.sin argument.evaluate(context)
end
def simplify
argument_simplified = argument.simplify
if argument_simplified.is_a? Number
return Math.sin( argument_simplified.evaluate )
end
Sine.new argument_simplified
end
def derive variable
Multiplication.new( Cosine.new( argument ), argument.derive( variable ) ).simplify
end
end
class Cosine < Unary
def initialize argument
@argument = argument
end
def evaluate context = {}
Math.cos argument.evaluate(context)
end
def simplify
argument_simplified = argument.simplify
if argument_simplified.is_a? Number
return Math.cos( argument_simplified.evaluate )
end
Cosine.new argument_simplified
end
def derive variable
Negation.new( Multiplication.new( Sine.new( argument ), argument.derive( variable ) ) ).simplify
end
end
class Negation < Unary
def evaluate context = {}
return -1 * argument.evaluate( context )
end
def simplify
argument_simplified = argument.simplify
if argument_simplified.is_a? Number
return Number.new( -1 * argument_simplified.evaluate )
end
Negation.new argument_simplified
end
def derive variable
return Negation.new( argument.derive variable ).simplify
end
end
class Binary < Expr
attr_reader :left_argument, :right_argument
def initialize left_argument, right_argument
@left_argument = left_argument
@right_argument = right_argument
end
def == expression
if not expression.class == self.class
return false
end
left_argument == expression.left_argument and right_argument == expression.right_argument
end
def + expression
if expression.is_a? Number and expression.evaluate == 0
return self
end
return Addition.new self, expression
end
def * expression
if expression.is_a? Number and expression.evaluate == 0
return Number.new 0
elsif expression.is_a? Number and expression.evaluate == 1
return self
end
return Multiplication.new self, expression
end
def self.build expression
case expression[0]
when :+
Addition.new Expr.build( expression[1] ), Expr.build( expression[2] )
when :*
Multiplication.new Expr.build( expression[1] ), Expr.build( expression[2] )
end
end
end
class Addition < Binary
def evaluate context = {}
return left_argument.evaluate( context ) + right_argument.evaluate( context )
end
def simplify
return left_argument.simplify + right_argument.simplify
end
def derive variable
Addition.new( left_argument.derive( variable ), right_argument.derive( variable ) ).simplify
end
end
class Multiplication < Binary
def evaluate context = {}
return left_argument.evaluate( context ) * right_argument.evaluate( context )
end
def simplify
return left_argument.simplify * right_argument.simplify
end
def derive variable
left_derivative = Multiplication.new( left_argument.derive( variable ), right_argument )
right_derivative = Multiplication.new( left_argument, right_argument.derive( variable ) )
Addition.new( left_derivative, right_derivative ).simplify
end
end

Лог от изпълнението

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Finished in 0.05032 seconds
13 examples, 0 failures

История (1 версия и 0 коментара)

Йордан обнови решението на 14.11.2012 13:21 (преди над 11 години)

+class Expr
+ def self.build expression
+ if expression[0] == :number
+ Number.new expression[1]
+ elsif expression.size == 2
+ Unary.build expression
+ else
+ Binary.build expression
+ end
+ end
+end
+
+class Number < Expr
+ attr_reader :argument
+
+ def initialize argument
+ @argument = argument
+ end
+
+ def == expression
+ if not expression.is_a? Number
+ return false
+ end
+ @argument == expression.argument
+ end
+
+ def evaluate _ = {}
+ self.argument
+ end
+
+ def simplify
+ self
+ end
+
+ def + expression
+ if argument == 0
+ return expression
+ end
+ if expression.is_a? Number
+ return Number.new( argument + expression.argument)
+ end
+ return Addition.new self, expression
+ end
+
+ def * expression
+ if argument == 0
+ return Number.new 0
+ elsif argument == 1
+ return expression
+ end
+ if expression.is_a? Number
+ return Number.new( argument * expression.argument)
+ end
+ return Multiplication.new self, expression
+ end
+
+ def derive _
+ Number.new 0
+ end
+end
+
+
+class Unary < Expr
+ attr_reader :argument
+
+ def initialize argument
+ @argument = argument
+ end
+
+ def == expression
+ if not expression.class == self.class
+ return false
+ end
+ @argument == expression.argument
+ end
+
+ def + expression
+ if expression.is_a? Number and expression.evaluate == 0
+ return self
+ end
+ return Addition.new self, expression
+ end
+
+ def * expression
+ if expression.is_a? Number and expression.evaluate == 0
+ return Number.new 0
+ elsif expression.is_a? Number and expression.evaluate == 1
+ return self
+ end
+ return Multiplication.new self, expression
+ end
+
+ def self.build expression
+ case expression[0]
+ when :variable
+ Variable.new expression[1]
+ when :-
+ Negation.new Expr.build expression[1]
+ when :sin
+ Sine.new Expr.build expression[1]
+ when :cos
+ Cosine.new Expr.build expression[1]
+ end
+ end
+end
+
+
+class Variable < Unary
+ def evaluate context = {}
+ if not context.has_key? argument
+ raise "the context #{ context.inspect } does not contains the variable: #{ self.inspect }"
+ end
+ context[argument]
+ end
+
+ def simplify
+ self
+ end
+
+ def derive variable
+ if variable == argument
+ return Number.new 1
+ end
+ return Number.new 0
+ end
+end
+
+
+class Sine < Unary
+ def evaluate context = {}
+ Math.sin argument.evaluate(context)
+ end
+
+ def simplify
+ argument_simplified = argument.simplify
+ if argument_simplified.is_a? Number
+ return Math.sin( argument_simplified.evaluate )
+ end
+ Sine.new argument_simplified
+ end
+
+ def derive variable
+ Multiplication.new( Cosine.new( argument ), argument.derive( variable ) ).simplify
+ end
+end
+
+
+class Cosine < Unary
+ def initialize argument
+ @argument = argument
+ end
+
+ def evaluate context = {}
+ Math.cos argument.evaluate(context)
+ end
+
+ def simplify
+ argument_simplified = argument.simplify
+ if argument_simplified.is_a? Number
+ return Math.cos( argument_simplified.evaluate )
+ end
+ Cosine.new argument_simplified
+ end
+
+ def derive variable
+ Negation.new( Multiplication.new( Sine.new( argument ), argument.derive( variable ) ) ).simplify
+ end
+end
+
+
+class Negation < Unary
+ def evaluate context = {}
+ return -1 * argument.evaluate( context )
+ end
+
+ def simplify
+ argument_simplified = argument.simplify
+ if argument_simplified.is_a? Number
+ return Number.new( -1 * argument_simplified.evaluate )
+ end
+ Negation.new argument_simplified
+ end
+
+ def derive variable
+ return Negation.new( argument.derive variable ).simplify
+ end
+end
+
+
+class Binary < Expr
+ attr_reader :left_argument, :right_argument
+
+ def initialize left_argument, right_argument
+ @left_argument = left_argument
+ @right_argument = right_argument
+ end
+
+ def == expression
+ if not expression.class == self.class
+ return false
+ end
+ left_argument == expression.left_argument and right_argument == expression.right_argument
+ end
+
+ def + expression
+ if expression.is_a? Number and expression.evaluate == 0
+ return self
+ end
+ return Addition.new self, expression
+ end
+
+ def * expression
+ if expression.is_a? Number and expression.evaluate == 0
+ return Number.new 0
+ elsif expression.is_a? Number and expression.evaluate == 1
+ return self
+ end
+ return Multiplication.new self, expression
+ end
+
+ def self.build expression
+ case expression[0]
+ when :+
+ Addition.new Expr.build( expression[1] ), Expr.build( expression[2] )
+ when :*
+ Multiplication.new Expr.build( expression[1] ), Expr.build( expression[2] )
+ end
+ end
+end
+
+
+class Addition < Binary
+ def evaluate context = {}
+ return left_argument.evaluate( context ) + right_argument.evaluate( context )
+ end
+
+ def simplify
+ return left_argument.simplify + right_argument.simplify
+ end
+
+ def derive variable
+ Addition.new( left_argument.derive( variable ), right_argument.derive( variable ) ).simplify
+ end
+end
+
+
+class Multiplication < Binary
+ def evaluate context = {}
+ return left_argument.evaluate( context ) * right_argument.evaluate( context )
+ end
+
+ def simplify
+ return left_argument.simplify * right_argument.simplify
+ end
+
+ def derive variable
+ left_derivative = Multiplication.new( left_argument.derive( variable ), right_argument )
+ right_derivative = Multiplication.new( left_argument, right_argument.derive( variable ) )
+ Addition.new( left_derivative, right_derivative ).simplify
+ end
+end