题目
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?
解题思路
如果n是3的x次方，那么以3为低对数后一定是一个整数，否则不是
参考了EbowTang的博客http://blog.csdn.net/ebowtang/article/details/50485622
代码
func isPowerOfThree(n int) bool {
if 0 >= n {
return false
}
res := math.Log10(float64(n)) / math.Log10(float64(3))
var res1 float64
res1 = res - float64(int(res))
fmt.Printf("res:%+v, res1:%+v, int res:%+v\n", res, res1, int(res))
if res1 < 1E-14 {
return true
}
return false
}
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