1657. Determine if Two Strings Are Close

Author: remy727

README.md

@@ -172,6 +172,7 @@
 | 1539 | Kth Missing Positive Number | [Ruby](./algorithms/ruby/1539-kth-missing-positive-number.rb) | Easy |
 | 1579 | Remove Max Number of Edges to Keep Graph Fully Traversable | [Ruby](./algorithms/ruby/1579-remove-max-number-of-edges-to-keep-graph-fully-traversable.rb) | Hard |
 | 1639 | Number of Ways to Form a Target String Given a Dictionary | [Ruby](./algorithms/ruby/1639-number-of-ways-to-form-a-target-string-given-a-dictionary.rb) | Hard |
+| 1657 | Determine if Two Strings Are Close | [Ruby](./algorithms/ruby/1657-determine-if-two-strings-are-close.rb) | Medium |
 | 1675 | Minimize Deviation in Array | [Ruby](./algorithms/ruby/1675-minimize-deviation-in-array.rb) | Hard |
 | 1679 | Max Number of K-Sum Pairs | [Ruby](./algorithms/ruby/1679-max-number-of-k-sum-pairs.rb) | Medium |
 | 1680 | Concatenation of Consecutive Binary Numbers | [Ruby](./algorithms/ruby/1680-concatenation-of-consecutive-binary-numbers.rb) | Medium |

algorithms/ruby/1657-determine-if-two-strings-are-close.rb

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+# frozen_string_literal: true
+
+# 1657. Determine if Two Strings Are Close
+# https://leetcode.com/problems/determine-if-two-strings-are-close
+# Medium
+
+=begin
+Two strings are considered close if you can attain one from the other using the following operations:
+
+Operation 1: Swap any two existing characters.
+For example, abcde -> aecdb
+Operation 2: Transform every occurrence of one existing character into another existing character, and do the same with the other character.
+For example, aacabb -> bbcbaa (all a's turn into b's, and all b's turn into a's)
+You can use the operations on either string as many times as necessary.
+
+Given two strings, word1 and word2, return true if word1 and word2 are close, and false otherwise.
+
+Example 1:
+Input: word1 = "abc", word2 = "bca"
+Output: true
+Explanation: You can attain word2 from word1 in 2 operations.
+Apply Operation 1: "abc" -> "acb"
+Apply Operation 1: "acb" -> "bca"
+
+Example 2:
+Input: word1 = "a", word2 = "aa"
+Output: false
+Explanation: It is impossible to attain word2 from word1, or vice versa, in any number of operations.
+
+Example 3:
+Input: word1 = "cabbba", word2 = "abbccc"
+Output: true
+Explanation: You can attain word2 from word1 in 3 operations.
+Apply Operation 1: "cabbba" -> "caabbb"
+Apply Operation 2: "caabbb" -> "baaccc"
+Apply Operation 2: "baaccc" -> "abbccc"
+
+Constraints:
+1 <= word1.length, word2.length <= 105
+word1 and word2 contain only lowercase English letters.
+=end
+
+# @param {String} word1
+# @param {String} word2
+# @return {Boolean}
+def close_strings(word1, word2)
+  word1, word2 = word1.chars, word2.chars
+
+  return false unless word1.uniq.sort.eql? word2.uniq.sort
+
+  word1.tally.values.sort.eql? word2.tally.values.sort
+end
+
+# **************** #
+#       TEST       #
+# **************** #
+
+require "test/unit"
+
+class Test_close_strings < Test::Unit::TestCase
+  def test_
+    assert_equal true, close_strings("abc", "bca")
+    assert_equal false, close_strings("a", "aa")
+    assert_equal true, close_strings("cabbba", "abbccc")
+  end
+end