Happy number
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.
Loop calculates the sum of squares of each digit until the result is 1 (returns True) or repeats (returns false)
classSolution { Public: BOOLIshappy (intN) {unordered_map<int,BOOL>m; intsum =Helper (n); while(Sum! =1) { if(M[sum] = =true) return false; M[sum]=true; Sum=Helper (sum); } return true; } intHelper (intN) {//sum of the squares of its digits intRET =0; while(n) {intdigit = n%Ten; N/=Ten; RET+ = (digit*digit); } returnret; }};
"Leetcode" 202. Happy number