LeetCode|Ugly Number

Ugly Number

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.

class Solution {
public:
bool isUgly(int num) {
if(num < 1) return false;
while((num & 1) == 0) num >>= 1;
while(num % 3 == 0) num /= 3;
while(num % 5 == 0) num /= 5;
return num == 1;
}
};

这里去掉括号竟然会WA，难道 == 的优先级要高于 & ？

while((num & 1) == 0) num >>= 1;