Question:
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.
Solution:
class Solution {public:bool isUgly(int num) { if(num == 0){ return false; } while(num != 1){ if(num %2 != 0 && num %3 != 0 && num % 5 != 0){ return false; } if(num%2 == 0){ num /= 2; } if(num%3 == 0){ num /= 3; } if(num%5 == 0){ num /= 5; } } return true; }};总结:
注意while判断条件是num!=1,而不是 num != 0
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