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  • LeetCode_202. Happy Number

    202. Happy Number

    Easy

    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: 

    Input: 19
    Output: true
    Explanation: 
    12 + 92 = 82
    82 + 22 = 68
    62 + 82 = 100
    12 + 02 + 02 = 1
    package leetcode.easy;
    
    public class HappyNumber {
    	public boolean isHappy(int n) {
    		if (n == 0) {
    			return false;
    		}
    		while (n != 1) {
    			int n2 = n;
    			n = 0;
    			while (n2 > 0) {
    				n += (n2 % 10) * (n2 % 10);
    				n2 /= 10;
    			}
    			if (n == 4) {
    				return false;
    			}
    		}
    		return true;
    	}
    
    	@org.junit.Test
    	public void test() {
    		System.out.println(isHappy(19));
    	}
    }
    
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  • 原文地址:https://www.cnblogs.com/denggelin/p/11720793.html
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