326. Power of Three，326powerofthree

326. Power of Three，326powerofthree

Given an integer, write a function to determine if it is a power of three.

Follow up:
Could you do it without using any loop / recursion?

判斷整數是不是3的冪數

1 bool isPowerOfThree(int n) {
2     // 1162261467 is 3^19,  3^20 is bigger than int  
3     return ( n>0 &&  1162261467%n==0);
4 }