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.
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Input: 6
Output: true
Explanation: 6 = 2 × 3
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-Example 2:
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Input: 8
Output: true
Explanation: 8 = 2 × 2 × 2
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Input: 14
Output: false
Explanation: 14 is not ugly since it includes another prime factor 7.
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1 is typically treated as an ugly number.
Input is within the 32-bit signed integer range: [−231, 231 − 1].
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判断一个数字是否为“丑数”,“丑数”是因子仅由 2,3,5 组成的数字.
实现
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public boolean (int num) {
if(num == 1) {
return true;
}
if(num == 0) {
return false;
}
while (num % 2 == 0) {
num = num >> 1;
}
while (num % 3 == 0) {
num = num / 3;
}
while (num % 5 == 0) {
num = num / 5;
}
return num == 1;
}
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参考
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