leetcode 202 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, 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: 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 this problem and creating all test cases.

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class Solution {public:bool isHappy(int n) {if(n==1) return true;map<int, int> exits;int cnt = 1, sum = 0;while(exits.count(n)==0) {exits[n] = 1;if(n==1) return true;while(n > 0) {sum += (n%10)*(n%10);n = n / 10;}n = sum;sum = 0;}return false;}}