LeetCode 1207. Unique Number of Occurrences

Author: raul-sauco

README.md

@@ -305,6 +305,7 @@ Solutions to LeetCode problems. The first column links to the problem in LeetCod
 | [1074. Number of Submatrices That Sum to Target][lc1074]                       | 🔴 Hard    | [![python](res/py.png)][lc1074py]                                   |
 | [1143. Longest Common Subsequence][lc1143]                                     | 🟠 Medium  | [![python](res/py.png)][lc1143py]                                   |
 | [1155. Number of Dice Rolls With Target Sum][lc1155]                           | 🟠 Medium  | [![python](res/py.png)][lc1155py]                                   |
+| [1207. Unique Number of Occurrences][lc1207]                                   | 🟢 Easy    | [![python](res/py.png)][lc1207py]                                   |
 | [1220. Count Vowels Permutation][lc1220]                                       | 🔴 Hard    | [![python](res/py.png)][lc1220py]                                   |
 | [1235. Maximum Profit in Job Scheduling][lc1235]                               | 🔴 Hard    | [![python](res/py.png)][lc1235py]                                   |
 | [1239. Maximum Length of a Concatenated String with Unique Characters][lc1239] | 🟠 Medium  | [![python](res/py.png)][lc1239py]                                   |
@@ -937,6 +938,8 @@ Solutions to LeetCode problems. The first column links to the problem in LeetCod
 [lc1143py]: leetcode/longest-common-subsequence.py
 [lc1155]: https://leetcode.com/problems/number-of-dice-rolls-with-target-sum/
 [lc1155py]: ../number-of-dice-rolls-with-target-sum.py
+[lc1207]: https://leetcode.com/problems/unique-number-of-occurrences/
+[lc1207py]: leetcode/unique-number-of-occurrences.py
 [lc1220]: https://leetcode.com/problems/count-vowels-permutation/
 [lc1220py]: leetcode/count-vowels-permutation.py
 [lc1235]: https://leetcode.com/problems/maximum-profit-in-job-scheduling/

leetcode/unique-number-of-occurrences.py

@@ -0,0 +1,56 @@
+# 1207. Unique Number of Occurrences
+# 🟢 Easy
+#
+# https://leetcode.com/problems/unique-number-of-occurrences/
+#
+# Tags: Array
+
+import timeit
+from collections import Counter
+from typing import List
+
+
+# A fast solution is to use Collections.Counter to get the count of
+# occurrences of each value, then check if the count of unique values
+# equals the total number of values, for example using a set.
+#
+# Time complexity: O(n)
+# Space complexity: O(m) - Where m is the number of unique values in the
+# input.
+#
+# Runtime: 39 ms, faster than 91.14%
+# Memory Usage: 14 MB, less than 72.74%
+class Solution:
+    def uniqueOccurrences(self, arr: List[int]) -> bool:
+        c = Counter(arr)
+        return len(c) == len(set(c.values()))
+
+
+def test():
+    executors = [
+        Solution,
+    ]
+    tests = [
+        [[1, 2, 2, 1, 1, 3], True],
+        [[1, 2], False],
+        [[-3, 0, 1, -3, 1, 1, 1, -3, 10, 0], True],
+    ]
+    for executor in executors:
+        start = timeit.default_timer()
+        for _ in range(1):
+            for col, t in enumerate(tests):
+                sol = executor()
+                result = sol.uniqueOccurrences(t[0])
+                exp = t[1]
+                assert result == exp, (
+                    f"\033[93m» {result} <> {exp}\033[91m for"
+                    + f" test {col} using \033[1m{executor.__name__}"
+                )
+        stop = timeit.default_timer()
+        used = str(round(stop - start, 5))
+        cols = "{0:20}{1:10}{2:10}"
+        res = cols.format(executor.__name__, used, "seconds")
+        print(f"\033[92m» {res}\033[0m")
+
+
+test()