D. J.:

- Added the leetcode problem and solution for 202 Happy Number

Author: nobodyPerfecZ

README.md

@@ -17,6 +17,7 @@ This repository contains awesome LeetCode problems and solutions written in Pyth
 - [125 Valid Palindrome](https://leetcode.com/problems/valid-palindrome/description/)
 - [169 Majority Element](https://leetcode.com/problems/majority-element/description/)
 - [189 Rotate Array](https://leetcode.com/problems/rotate-array/description/)
+- [202 Happy Number](https://leetcode.com/problems/happy-number/description/)
 - [205 Isomorphic Strings](https://leetcode.com/problems/isomorphic-strings/description/)
 - [242 Valid Anagram](https://leetcode.com/problems/valid-anagram/description/)
 - [290 Word Pattern](https://leetcode.com/problems/word-pattern/description/)

awesome_python_leetcode/_202_happy_number.py

@@ -0,0 +1,22 @@
+class Solution:
+    def sum_of_squares(self, n: int) -> int:
+        return sum(int(digit) ** 2 for digit in str(abs(n)))
+
+    def isHappy(self, n: int) -> bool:
+        """
+        Write an algorithm to determine if a number n is happy.
+
+        A happy number is a number defined by the following process:
+        - Starting with any positive integer, replace the number by the sum of the squares of its digits.
+        - Repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1.
+        - Those numbers for which this process ends in 1 are happy.
+
+        Return true if n is a happy number, and false if not.
+        """
+        values = {}
+        while n != 1:
+            if n in values:
+                return False
+            values[n] = True
+            n = self.sum_of_squares(n)
+        return True

tests/test_202_happy_number.py

@@ -0,0 +1,15 @@
+import pytest
+
+from awesome_python_leetcode._202_happy_number import Solution
+
+
+@pytest.mark.parametrize(
+    argnames=["n", "expected"],
+    argvalues=[
+        (19, True),
+        (2, False),
+    ],
+)
+def test_func(n: int, expected: bool):
+    is_happy = Solution().isHappy(n)
+    assert is_happy == expected