0151-reverse-words-in-a-string.rb

# frozen_string_literal: true

# 151. Reverse Words in a String
# https://leetcode.com/problems/reverse-words-in-a-string
# Medium

=begin
Given an input string s, reverse the order of the words.

A word is defined as a sequence of non-space characters. The words in s will be separated by at least one space.

Return a string of the words in reverse order concatenated by a single space.

Note that s may contain leading or trailing spaces or multiple spaces between two words. The returned string should only have a single space separating the words. Do not include any extra spaces.

Example 1:
Input: s = "the sky is blue"
Output: "blue is sky the"

Example 2:
Input: s = "  hello world  "
Output: "world hello"
Explanation: Your reversed string should not contain leading or trailing spaces.

Example 3:
Input: s = "a good   example"
Output: "example good a"
Explanation: You need to reduce multiple spaces between two words to a single space in the reversed string.


Constraints:
* 1 <= s.length <= 104
* s contains English letters (upper-case and lower-case), digits, and spaces ' '.
* There is at least one word in s.
=end

# @param {String} s
# @return {String}
def reverse_words(s)
  s.split(" ").reverse.join(" ")
end

# **************** #
#       TEST       #
# **************** #

require "test/unit"
class Test_length_of_longest_substring < Test::Unit::TestCase
  def test_
    assert_equal "blue is sky the", reverse_words("the sky is blue")
    assert_equal "world hello", reverse_words("  hello world  ")
    assert_equal "example good a", reverse_words("a good   example")
  end
end