Денис обнови решението на 10.01.2016 19:18 (преди над 8 години)
+module Formula
+
+ def add(parameters)
+ check_arguments_at_least('ADD', 2, parameters)
+ parameters.reduce(&:+)
+ end
+
+ def multiply(parameters)
+ check_arguments_at_least('MULTIPLY', 2, parameters)
+ parameters.reduce(&:*)
+ end
+
+ def subtract(parameters)
+ check_arguments('SUBTRACT', 2, parameters)
+ parameters[0] - parameters[1]
+ end
+
+ def divide(parameters)
+ check_arguments('DIVIDE', 2, parameters)
+ parameters[0] / parameters[1]
+ end
+
+ def mod(parameters)
+ check_arguments('MOD', 2, parameters)
+ parameters[0] % parameters[1]
+ end
+
+ def check_arguments(formula, expected, parameters)
+ if parameters.size != expected
+ raise Spreadsheet::Error, "Wrong number of arguments for '#{formula}': "\
+ "expected #{expected}, got #{parameters.size}"
+ end
+ end
+
+ def check_arguments_at_least(formula, expected, parameters)
+ if parameters.size < expected
+ raise Spreadsheet::Error, "Wrong number of arguments for '#{formula}': "\
+ "expected at least #{expected}, got #{parameters.size}"
+ end
+ end
+
+end
+
+module Evaluate
+ NUMBER_PATTERN = /\A(\d|\.)+\z/
+ FORMULA_PATTERN = %r{
+ \A #start of string
+ [A-Z]+ #formula
+ \( #opening bracket
+ (?<param>([A-Z]+\d+|\d+\.?\d*))?(\s*,\s*\g<param>?)* #parameters
+ \) #closing bracket
+ \z #end of string
+ }x
+ VALID_FORMULA = ["ADD", "MULTIPLY", "SUBTRACT", "DIVIDE", "MOD"]
+
+ def evaluate_cell(cell_index)
+ cell_content = cell_at_internal(cell_index.strip)
+ evaluate_content(cell_content)
+ end
+
+ def evaluate_content(cell_content)
+ if cell_content.start_with?("=")
+ evaluate_expression(cell_content[1..(-1)].strip)
+ else
+ evaluate_non_expression(cell_content)
+ end
+ end
+
+ def evaluate_non_expression(content)
+ if /\A\d/ === content
+ Float(content)
+ else
+ content
+ end
+ end
+
+ def evaluate_expression(expression)
+ case expression
+ when Spreadsheet::TABLE_CELL_PATTERN then evaluate_cell(expression)
+ when NUMBER_PATTERN then Float(expression)
+ when FORMULA_PATTERN then evaluate_formula_expression(expression)
+ else raise Spreadsheet::Error, "Invalid expression '#{expression}'"
+ end
+ end
+
+ def evaluate_formula_expression(expression)
+ parameters_string = /\([A-Z\d,\s\.]*\)/.match(expression)[0][1..(-2)]
+ parameters = parameters_string.split(",").map(&:strip)
+ formula = /[A-Z]+/.match(expression)[0]
+ evaluate_formula(formula, evaluate_parameters(parameters))
+ end
+
+ def evaluate_parameters(parameters)
+ parameters.map do |parameter|
+ if /\A\d/ === parameter
+ Float(parameter)
+ else
+ evaluate_cell(parameter)
+ end
+ end
+ end
+
+ def evaluate_formula(formula, parameters)
+ validate_formula(formula)
+ send(formula.downcase.to_sym, parameters)
+ end
+
+ def validate_formula(formula)
+ unless VALID_FORMULA.include?(formula)
+ raise Spreadsheet::Error, "Unknown function '#{formula}'"
+ end
+ end
+
+end
+
+module SpreadsheetInternal
+
+ def validate_cell_index_format(cell_index)
+ unless Spreadsheet::TABLE_CELL_PATTERN === cell_index
+ raise Spreadsheet::Error, "Invalid cell index #{cell_index}"
+ end
+ end
+
+ def index_to_row_and_column(cell_index)
+ column, row = cell_index.scan(/\A[[:alpha:]]+|[[:digit:]]+\z/)
+ row = row.to_i - 1
+ column = column.split("").map() do |letter|
+ letter.ord - "A".ord
+ end.reduce(&:+) + 26 * (column.size - 1)
+ [row, column]
+ end
+
+ def finalize_output(cell_output)
+ if String === cell_output
+ cell_output
+ else
+ integer, float = cell_output.to_i, cell_output.to_f
+ integer == float ? integer.to_s : '%.2f' % cell_output
+ end
+ end
+
+end
+
+class Spreadsheet
+ include SpreadsheetInternal
+ include Formula
+ include Evaluate
+
+ TABLE_CELL_PATTERN = /\A[A-Z]+\d+\z/
+
+ def initialize(tab_separated_values = "")
+ input = tab_separated_values.strip
+ @sheet = input.split("\n").map(&:strip).map do |line|
+ line.split(/\s{2,}|\t/)
+ end
+ end
+
+ def empty?
+ @sheet.empty?
+ end
+
+ def cell_at(cell_index)
+ finalize_output(cell_at_internal(cell_index))
+ end
+
+ def cell_at_internal(cell_index)
+ validate_cell_index_format(cell_index)
+ row, column = index_to_row_and_column(cell_index)
+ if @sheet.size <= row or @sheet.first.size <= column
+ raise Error, "Cell '#{cell_index}' does not exist"
+ end
+ @sheet[row][column]
+ end
+
+ def [](cell_index)
+ finalize_output(evaluate_cell(cell_index))
+ end
+
+ def to_s
+ @sheet.map do |line|
+ line.map {|content| finalize_output(evaluate_content(content))}.join("\t")
+ end.join("\n")
+ end
+
+end
+
+class Spreadsheet::Error < Exception
+
+end