zoukankan      html  css  js  c++  java
  • [LeetCode] Happy Number

    Happy Number


    Total Accepted: 35195 Total Submissions: 106936 Difficulty: 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: 19 is a happy number

    • 12 + 92 = 82
    • 82 + 22 = 68
    • 62 + 82 = 100
    • 12 + 02 + 02 = 1

    Credits:
    Special thanks to @mithmatt and @ts for adding this problem and creating all test cases.

    class Solution {
    public:
        bool isHappy(int n) {
            if (n < 0) return false;
            unordered_set<int> loop;
            while (true) {
                if (n == 1) return true;
                int t = n;
                int round = 0;
                while (t > 0) {
                    int p = t % 10;
                    round += p * p;
                    t /= 10;
                }
                
                if (loop.find(round) != loop.end()) return false;
                else loop.insert(round);
                n = round;
            }
            return true;
        }
    };

    这题用JS 就不好搞了,因为运算老是变成浮点数。。。思路比较简单,同样使用哈希表来监测loop。

  • 相关阅读:
    事件的基本概念
    c# 语法 字符串内插
    tcp 的编程例子
    Action 语法的简介
    wcf 的小介绍
    Socket编程
    c# base new 等关键字基础
    虚函数和继承的关系
    arraylist,list ,数组区别
    Python爬虫-selenium模拟豆瓣电影鼠标下拉
  • 原文地址:https://www.cnblogs.com/agentgamer/p/4864738.html
Copyright © 2011-2022 走看看