Happy Number

Author: saurabhchris1

Happy_Number.py

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+# Write an algorithm to determine if a number 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,
+# and 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 numbers.
+#
+# Example:
+#
+# Input: 19
+# Output: true
+# Explanation:
+# 12 + 92 = 82
+# 82 + 22 = 68
+# 62 + 82 = 100
+# 12 + 02 + 02 = 1
+
+
+class Solution:
+    def isHappy(self, n):
+        slow = n
+        fast = self.getNum(n)
+
+        while fast != 1 and slow != fast:
+            slow = self.getNum(slow)
+            fast = self.getNum(self.getNum(fast))
+
+        return fast == 1
+
+    def getNum(self, num):
+        res = 0
+        while num > 0:
+            res += (num % 10) ** 2
+            num = num // 10
+        return res