Code test

code-test.rb

#! /usr/bin/env ruby

# Write a function that returns true if the brackets in a given string are balanced.
# Balanced means that every parenthesis/bracket or brace that is opened must be closed
# And it must be closed in the right order (Always close the last symbol you opened)
# The function must handle parens (), square brackets [], and curly braces {}.

# "(a[0]+b[2c[6]]) {24 + 53}" should return true
# "f(e(d))" should return true
# "[()]{}([])" should return true
# "((b)" should return false
# "(c]" should return false
# "{(a[])" should return false
# "([)]" should return false
# ")(" should return false
# "" should return false

class Char
  def initialize(char)
    @char = char
  end

  def bracket?
    %w[{ } [ ] ( )].include? @char
  end

  def open?
    %W[{ \[ (].include? @char
  end

  def inverse
    {
      '(' => ')',
      ')' => '(',
      '{' => '}',
      '}' => '{',
      '[' => ']',
      ']' => '['
    }[@char]
  end

  def to_s
    @char
  end
end

def parse_brackets(input)
  return false if input.empty?

  stack = []

  input.chars.each do |char|
    char = Char.new(char)

    next unless char.bracket?

    if char.open?
      stack << char
    elsif stack.last.to_s == char.inverse
      stack.pop
    else
      return false
    end
  end

  stack.empty?
end

pp parse_brackets('(a[0]+b[2c[6]]) {24 + 53}')
pp parse_brackets('f(e(d))')
pp parse_brackets('[()]{}([])')
pp !parse_brackets('((b)')
pp !parse_brackets('(c]')
pp !parse_brackets('{(a[])')
pp !parse_brackets('([)]')
pp !parse_brackets(')(')
pp !parse_brackets('')