LeetCode -- Happy Number

LeetCode -- Happy Number

Description:
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




Determines whether a number is happy number.
Follow the description to accumulate the square of each person and obtain a new number. If the sum is 1, true is returned. Otherwise, the computed number is saved using a hash. If a hash already exists, false is returned.


Implementation Code:

public class Solution {    public bool IsHappy(int n) {        var digs = n.ToString();    var hash = new Dictionary
 
  ();        while(true){    int r = 0;    for(var i = 0;i < digs.Length; i++){    var x = int.Parse(digs[i].ToString());    r += x * x;    }    if(r == 1){    return true;    }    if(!hash.ContainsKey(r)){    hash.Add(r, true);    digs = r.ToString();    }    else{    return false;    }    }    }}