Problem Definition:
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 and replace the number by the Sum of the squares of its digits, and repeat the process until the number equals 1 (where it would stay), or it loops Endl essly in a cycle which does not include 1. Those numbers for which this process ends in 1 is happy numbers.
Example: is a happy number
- 12 + 92 = 82
- 82 + 22 = 68
- 62 + 82 = 100
- 12 + 02 + 02 = 1
Solution:
1 defIshappy (self,n):2d={}#use a dictionary to store n3 whileTrue:4 ifN==1:#once a certain sum of squares is 1, it is certainly happy5 returnTrue6 ifN not inchD:7D[n]=0#0 is only a mark8n=self.getsum (n)9 Else:#repeated and not 1 squared sum, not happyTen returnFalse One defgetsum (self,n): As=0 - whilen!=0: -A=n%10 theN=n/10 -S+=a**2 - returnS
leetcode#202 Happy Number