Java for LeetCode 202 Happy Number

標籤：

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
解題思路：

HashMap，JAVA實現如下：

    public boolean isHappy(int n) {        HashMap<Integer,Boolean> hm=new HashMap<Integer,Boolean>();        while(!hm.containsKey(n)&&n!=1){        hm.put(n, true);        n=HappyTime(n);        }        return n==1;    }   static public int HappyTime(int n){    int res=0;    while(n!=0){    res+=(n%10)*(n%10);    n/=10;    }    return res;    }

 

Java for LeetCode 202 Happy Number