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

设定循环，如果最后无法得到1，必定存在某次情况使得得到的值等于之前生成过的值。

*js的Array没有内置contains/include函数，需要自己添加。

Array.prototype.contains = function (x) {
for (var i in this)
if (this[i] == x)
return true
return false
}

var isHappy = function(n) {
var temp = []
var s = n.toString()
while (true){
var sum = 0
for (var i=0;i<s.length;i++)
sum += s[i]*s[i]
if(sum == 1)
return true
else if (temp.contains(sum))
return false
temp.push(sum)
s = sum.toString()
}
}