[Leetcode] 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

The happiness number has the following characteristics: In the given carry system, the number of all digits (digits) of the sum of squares, the new number obtained once again the sum of squares of all digits, so repeated, the final result must be 1.

The number of non-happy numbers has the following characteristics: the sum of the squares of all the unhappy numbers is calculated, and the last one will enter the 4→16→37→58→89→145→42→20→4 cycle.

So the outer loop: to determine whether it is the number of happy and non-happy. The inner Loop calculates the happy number decomposition of N.

classSolution { Public:    BOOLIshappy (intN) { while(n! =1&& n! =4) {            intsum =0, TMP =0;  while(n! =0) {tmp= n%Ten; Sum+ = tmp *tmp; N/=Ten; } N=sum; }        returnn = =1; }};//3 Ms

[Leetcode] Happy number