[leetcode-263-Ugly Number]
阿新 • • 發佈:2017-05-20
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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.
思路:
將num一直除以 2,3,5,一直到沒法除為止,判斷結果是否為1。
bool isUgly(int num) { if(num<=0) return false; if(num == 1) return true; while(num % 2 == 0)num/=2; while(num % 3 == 0)num/=3; while(num % 5 == 0)num/=5; if(num!=1) return false; return true; }
[leetcode-263-Ugly Number]