题目
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.
Example 1:
Input: 6
Output: true
Explanation: 6 = 2 × 3
Example 2:
Input: 8
Output: true
Explanation: 8 = 2 × 2 × 2
Example 3:
Input: 14
Output: false
Explanation: 14 is not ugly since it includes another prime factor 7.
Note:
1 is typically treate as the first ugly number
###
class Solution(object):
def isUgly(self, num):
"""
:type num: int
:rtype: bool
"""
if num ==0:
return False
if num == 1:
return True
pms = [2,3,5]
for x in pms:
while num%x==0:
num /= x
return num==1
也可以这样
public boolean isUgly(int num) {
if (num <= 0) {
return false;
}
while(num%30==0) num = num/30;
while(num%15==0) num = num/15;
while(num%10==0) num = num/10;
while(num%5==0) num = num/5;
while(num%3==0) num = num/3;
while(num%2==0) num = num/2;
if(num==1) return true;
else return false;
}
即约掉几个更大的数字.





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