(LeetCode)Happy Number -- 寻找快乐数
2016-08-22 11:05
295 查看
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.
Subscribe to see which companies asked this question
解题分析:
题意就是寻找一个符合每一位的平方和相加最后等于 1 的数,被称为Happy Number.
方法一,循环判断,如果满足要求,则返回True,不满足,返回False, 判断循环的话,可以用Dict记录之前的,重复出现
视为循环,则返回False.
# -*- coding:utf-8 -*-
__author__ = 'jiuzhang'
class Solution(object):
def isHappy(self, n):
num_dict = {}
while True:
num_dict
= True
sum = 0
while(n > 0):
sum += (n % 10) * (n % 10)
n /= 10
if sum == 1:
return True
elif sum in num_dict:
return False
else:
n = sum
方法二 : 在方法一的基础上进行修改,先计算出100以下的Happy Number 。其余的在套用公式。
# -*- coding:utf-8 -*-
__author__ = 'jiuzhang'
'''
optimized code
'''
class Solution(object):
def isHappy(self, n):
happySet = set([1, 7, 10, 13, 19, 23, 28, 31, 32, 44, 49, 68, 70, 79, 82, 86, 91, 94, 97])
while n > 99:
n = sum([int(x) * int(x) for x in list(str(n))])
return n in happySet
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.
Subscribe to see which companies asked this question
解题分析:
题意就是寻找一个符合每一位的平方和相加最后等于 1 的数,被称为Happy Number.
方法一,循环判断,如果满足要求,则返回True,不满足,返回False, 判断循环的话,可以用Dict记录之前的,重复出现
视为循环,则返回False.
# -*- coding:utf-8 -*-
__author__ = 'jiuzhang'
class Solution(object):
def isHappy(self, n):
num_dict = {}
while True:
num_dict
= True
sum = 0
while(n > 0):
sum += (n % 10) * (n % 10)
n /= 10
if sum == 1:
return True
elif sum in num_dict:
return False
else:
n = sum
方法二 : 在方法一的基础上进行修改,先计算出100以下的Happy Number 。其余的在套用公式。
# -*- coding:utf-8 -*-
__author__ = 'jiuzhang'
'''
optimized code
'''
class Solution(object):
def isHappy(self, n):
happySet = set([1, 7, 10, 13, 19, 23, 28, 31, 32, 44, 49, 68, 70, 79, 82, 86, 91, 94, 97])
while n > 99:
n = sum([int(x) * int(x) for x in list(str(n))])
return n in happySet
相关文章推荐
- [LeetCode] 202. Happy Number 快乐数
- 202.leetcode Happy Number(easy)[数学 快乐数]
- [LeetCode]202. Happy Number 快乐数
- [LeetCode] Happy Number 快乐数
- leetcode 202 Happy Number
- LeetCode | 141. Linked List Cycle 寻找链表中的环,简单题
- [leetcode] 202. Happy Number 解题报告
- Linked List Cycle leetcode II java (寻找链表环的入口)
- LeetCode第202题. Happy Number
- leetcode 260. Single Number III-寻找单身狗|位运算
- [LeetCode] Find Bottom Left Tree Value 寻找最左下树结点的值
- [leetcode: Python]202.Happy Number
- 【LeetCode】162.Find Peak Element 寻找峰值(二分法) - Medium
- [Leetcode,python] Find All Numbers Disappeared in an Array 寻找数组中消失的数字
- LeetCode 刷题: Happy Number 的判断
- leetcode 202. Happy Number
- leetcode| Happy Number
- leetcode202. Happy Number
- Leetcode|happy number
- leetcode 501. Find Mode in Binary Search Tree 寻找出现最多次数的元素 + 二叉搜索树BST的中序遍历