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:19 is a happy number
- 12 + 92 = 82
- 82 + 22 = 68
- 62 + 82 = 100
- 12 + 02 + 02 = 1
Credits:
Special thanks to @mithmatt and @ts for adding the problem and creating all test cases.
[Solution]
If it is not happy number, the result will be a loop, record all results with set, False if repeat occurs
1 BOOLIshappy (intN)2 {3 Set<int>table;4 5 Table.insert (n);6 while(1)7 {8 intK =0;9 while(n)Ten { OneK + = (n%Ten) * (n%Ten); AN/=Ten; - } - if(k = =1) the return true; - if(Table.find (k)! =table.end ()) - return false; -n =K; + Table.insert (n); - } +}
[Leetcode] 202. Happy number