263. Ugly Number

problem

solution

class Solution {
public:
    bool isUgly(int n) {
        if(n<1)  return false;
        while(n%2==0) n>>=1;
        while(n%3==0) n/=3;
        while(n%5==0) n/=5;
        return n==1;   
    }
};

analysis

• time complexity O(logn)
• space complexity O(1)