# Leetcode 202 Happy Number

Source: Internet
Author: User

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

Set the loop, if the last cannot get 1, there must be a loop so that the resulting value is equal to the previously generated value.

The *JS array does not have a built-in contains/include function and needs to be added yourself.

`Array.prototype.contains =function(x) { for(varIinch  This)        if( This[I] = =x)return true    return false}varIshappy =function(n) {vartemp = []    vars =n.tostring () while(true){        varsum = 0 for(vari=0;i<s.length;i++) Sum+ = s[i]*S[i]if(Sum = = 1)             return true        Else if(Temp.contains (sum))return falseTemp.push (sum) s=sum.tostring ()}}`

Leetcode 202 Happy Number

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