796 and 3163

Author: remy727

README.md

@@ -270,6 +270,7 @@
 | 783 | Minimum Distance Between BST Nodes | [Ruby](./algorithms/ruby/0783-minimum-distance-between-bst-nodes.rb) [Python3](./algorithms/python3/0783-minimum-distance-between-bst-nodes.py) | Easy |
 | 785 | Is Graph Bipartite? | [Ruby](./algorithms/ruby/0785-is-graph-bipartite.rb) | Medium |
 | 790 | Domino and Tromino Tiling | [Ruby](./algorithms/ruby/0790-domino-and-tromino-tiling.rb) | Medium |
+| 796 | Rotate String | [Ruby](./algorithms/ruby/0796-rotate-string.rb) | Easy |
 | 799 | Champagne Tower | [Ruby](./algorithms/ruby/0799-champagne-tower.rb) | Medium |
 | 802 | Find Eventual Safe States | [Ruby](./algorithms/ruby/0802-find-eventual-safe-states.rb) | Medium |
 | 808 | Soup Servings | [Ruby](./algorithms/python3/0808-soup-servings.py) | Medium |
@@ -515,6 +516,7 @@
 | 2842 | Difference Between Ones and Zeros in Row and Column | [Ruby](./algorithms/ruby/2842-difference-between-ones-and-zeros-in-row-and-column.rb) | Medium |
 | 2849 | Determine if a Cell Is Reachable at a Given Time | [Ruby](./algorithms/ruby/2849-determine-if-a-cell-is-reachable-at-a-given-time) | Medium |
 | 2966 | Divide Array Into Arrays With Max Difference | [Ruby](./algorithms/ruby/2966-divide-array-into-arrays-with-max-difference) | Medium |
+| 3163 | String Compression III | [Ruby](./algorithms/ruby/3163-string-compression-iii.rb) | Medium |
 
 ### Database
 | # | Title | Solution | Difficulty |

algorithms/ruby/0796-rotate-string.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+# 796. Rotate String
+# Easy
+# https://leetcode.com/problems/rotate-string
+
+=begin
+Given two strings s and goal, return true if and only if s can become goal after some number of shifts on s.
+A shift on s consists of moving the leftmost character of s to the rightmost position.
+* For example, if s = "abcde", then it will be "bcdea" after one shift.
+
+Example 1:
+Input: s = "abcde", goal = "cdeab"
+Output: true
+Example 2:
+Input: s = "abcde", goal = "abced"
+Output: false
+
+Constraints:
+* 1 <= s.length, goal.length <= 100
+* s and goal consist of lowercase English letters.
+=end
+
+# @param {String} s
+# @param {String} goal
+# @return {Boolean}
+def rotate_string(s, goal)
+  return false if s.length != goal.length
+  (s + s).include?(goal)
+end
+
+# **************** #
+#       TEST       #
+# **************** #
+
+require "test/unit"
+class Test_rotate_string < Test::Unit::TestCase
+  def test_
+    assert_equal true, rotate_string("abcde", "cdeab")
+    assert_equal false, rotate_string("abcde", "abced")
+  end
+end

algorithms/ruby/3163-string-compression-iii.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+# 3163. String Compression III
+# Medium
+# https://leetcode.com/problems/string-compression-iii/description/
+
+=begin
+Given a string word, compress it using the following algorithm:
+* Begin with an empty string comp. While word is not empty, use the following operation:
+  * Remove a maximum length prefix of word made of a single character c repeating at most 9 times.
+  * Append the length of the prefix followed by c to comp.
+Return the string comp.
+
+Example 1:
+Input: word = "abcde"
+Output: "1a1b1c1d1e"
+Explanation:
+Initially, comp = "". Apply the operation 5 times, choosing "a", "b", "c", "d", and "e" as the prefix in each operation.
+For each prefix, append "1" followed by the character to comp.
+
+Example 2:
+Input: word = "aaaaaaaaaaaaaabb"
+Output: "9a5a2b"
+Explanation:
+Initially, comp = "". Apply the operation 3 times, choosing "aaaaaaaaa", "aaaaa", and "bb" as the prefix in each operation.
+* For prefix "aaaaaaaaa", append "9" followed by "a" to comp.
+* For prefix "aaaaa", append "5" followed by "a" to comp.
+* For prefix "bb", append "2" followed by "b" to comp.
+
+Constraints:
+* 1 <= word.length <= 2 * 105
+* word consists only of lowercase English letters.
+=end
+
+# @param {String} word
+# @return {String}
+def compressed_string(word)
+  word.gsub(/(.)\1{,8}/) { _1.size.to_s + $1 }
+end
+
+# **************** #
+#       TEST       #
+# **************** #
+
+require "test/unit"
+class Test_compressed_string < Test::Unit::TestCase
+  def test_
+    assert_equal "1a1b1c1d1e", compressed_string("abcde")
+    assert_equal "9a5a2b", compressed_string("aaaaaaaaaaaaaabb")
+  end
+end