1207. Unique Number of Occurrences

Author: remy727

README.md

@@ -151,6 +151,7 @@
 | 1129 | Shortest Path with Alternating Colors | [Ruby](./algorithms/ruby/1129-shortest-path-with-alternating-colors.rb) | Medium |
 | 1155 | Number of Dice Rolls With Target Sum | [Ruby](./algorithms/ruby/1155-number-of-dice-rolls-with-target-sum.rb) | Medium |
 | 1162 | As Far from Land as Possible | [Ruby](./algorithms/ruby/1162-as-far-from-land-as-possible.rb) | Medium |
+| 1207 | Unique Number of Occurrences | [Ruby](./algorithms/ruby/1207-unique-number-of-occurrences.rb) | Easy |
 | 1254 | Number of Closed Islands | [Ruby](./algorithms/ruby/1254-number-of-closed-islands.rb) | Medium |
 | 1319 | Number of Operations to Make Network Connected | [Ruby](./algorithms/ruby/1319-number-of-operations-to-make-network-connected.rb) | Medium |
 | 1372 | Longest ZigZag Path in a Binary Tree | [Ruby](./algorithms/ruby/1372-longest-zigzag-path-in-a-binary-tree.rb) | Medium |

algorithms/ruby/1207-unique-number-of-occurrences.rb

@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+# 1207. Unique Number of Occurrences
+# https://leetcode.com/problems/unique-number-of-occurrences
+# Easy
+
+=begin
+Given an array of integers arr, return true if the number of occurrences of each value in the array is unique or false otherwise.
+
+Example 1:
+Input: arr = [1,2,2,1,1,3]
+Output: true
+Explanation: The value 1 has 3 occurrences, 2 has 2 and 3 has 1. No two values have the same number of occurrences.
+
+Example 2:
+Input: arr = [1,2]
+Output: false
+
+Example 3:
+Input: arr = [-3,0,1,-3,1,1,1,-3,10,0]
+Output: true
+
+Constraints:
+1 <= arr.length <= 1000
+-1000 <= arr[i] <= 1000
+=end
+
+# @param {Integer[]} arr
+# @return {Boolean}
+def unique_occurrences(arr)
+  !arr.tally.values.uniq!
+end
+
+# **************** #
+#       TEST       #
+# **************** #
+
+require "test/unit"
+class Test_unique_occurrences < Test::Unit::TestCase
+  def test_
+    assert_equal true, unique_occurrences([1, 2, 2, 1, 1, 3])
+    assert_equal false, unique_occurrences([1, 2])
+    assert_equal true, unique_occurrences([-3, 0, 1, -3, 1, 1, 1, -3, 10, 0])
+  end
+end