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0326.go
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0326.go
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// Source: https://leetcode.com/problems/power-of-three
// Title: Power of Three
// Difficulty: Easy
// Author: Mu Yang <http://muyang.pro>
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Given an integer n, return true if it is a power of three. Otherwise, return false.
//
// An integer n is a power of three, if there exists an integer x such that n == 3x.
//
// Example 1:
//
// Input: n = 27
// Output: true
//
// Example 2:
//
// Input: n = 0
// Output: false
//
// Example 3:
//
// Input: n = 9
// Output: true
//
// Constraints:
//
// -2^31 <= n <= 2^31-1
//
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
package main
func isPowerOfThree(n int) bool {
if n < 1 {
return false
}
for n%3 == 0 {
n /= 3
}
return n == 1
}
// 1162261467 is the max power of three in 32-bit integer
func isPowerOfThree2(n int) bool {
return n > 0 && 1162261467%n == 0
}