神奇的数字 202. Happy Number
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.
参考的别人的答案,因为我没读懂题~
class Solution(object):
def isHappy(self, n):
"""
:type n: int
:rtype: bool
"""
seen = []
while n not in seen:
seen.append(n)
n = sum([int(x) **2 for x in str(n)])
return n == 1
Write a program to check whether a given number is an ugly number.
Ugly numbers are positive numbers whose prime factors only include 2,
3, 5
. For example, 6, 8
are ugly while 14
is
not ugly since it includes another prime factor 7
.
Note that 1
is typically treated as an ugly
number.
Credits:
Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.
class Solution(object):
def isUgly(self, num):
"""
:type num: int
:rtype: bool
"""
if (num==0):
return False
for x in [2,3,5]:
while(num%x==0):
num=num/x
return num==1
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神奇的数字 202. Happy Number